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73-87 Chevy _ GMC Trucks => Fuel Systems and Drivability => Topic started by: Steve341 on May 12, 2013, 10:16:33 am

Title: Quadrajet Carberator
Post by: Steve341 on May 12, 2013, 10:16:33 am
Grrr This truck is really starting to get my goat now. I got that 75 C20 Scottsdale camper special  with the 454, as you guys have helped me with its hesitation problem. Thought I got the truck running perfect just by changing the small fuel filter in the carb, and the main one under the truck. I drove it around lots in the past 3 days, drove it HARD and no problems at all. Got the truck box camper loaded in the back, a 3200 pounder dry weight I may add that has been on that truck since it was brand new I've been told. It is a 1974 Scamper 12 footer. Heavy unit. Anyways loaded it up in the truck box, took it for a spin slow speed working fine leaving town. I took it on the highway and put er to the mat, still fine. And about 3 minutes into our little test drive as I wanted to see how this beast would yard this camper no problem of course and I have never driven with it on, wanted to see what it was like, it hesitates, I back off on the gas pedal, floor it again and then she quits on me. Tried starting it again, nothing not even a fire, before we got out of the cab. Real STRONG gas smell thought it was coming from the back of the truck, no. Popped the hood up and the carb is soaked in gas and a nice pool of fuel on the intake sizzling away. Called the guy I bought the rig off of, he came down and checked it out. Appears the choke was stuck open and he could not get it to close. He said he would hold it closed and go in and try cranking it over so I did and we had a small fire, thankfully had a fire extinguisher in the camper. Then he just pulled it back home with his tundra. Is it time to rebuild or replace the carburetor? He said he would get a rebuild kit and fix it up.
Title: Re: Quadrajet Carberator
Post by: Stewart G Griffin on May 12, 2013, 02:38:08 pm
How soon do you need the truck?
Title: Quadrajet Carberator
Post by: Steve341 on May 12, 2013, 06:45:39 pm
Last weekend in may
Title: Re: Quadrajet Carberator
Post by: Jason S on May 12, 2013, 08:42:14 pm
What you describe, sounds like the float may be hanging up. 

If the truck has just sat for a while, in my opinion, I'd clean and put in a rebuild kit to the current carburetor.  If there were not any major issues with the original carburetor beforehand, other than the truck having set for a while, I would just clean the carburetor thoroughly and install the new gaskets; I would check the float setting and other adjustments, but wouldn't touch them at the time of rebuild. 
Title: Quadrajet Carberator
Post by: Steve341 on May 18, 2013, 03:31:44 pm
The carb number is 7045212. I was messing with it today. It's spraying fuel straight up the choke above the primaries.
Title: Quadrajet Carberator
Post by: Steve341 on May 18, 2013, 03:41:17 pm
I got the carb off the motor. Going into Edmonton see if I can find a rebuild kit
Title: Re: Quadrajet Carberator
Post by: 74 C-10 Shorty on May 22, 2013, 09:40:32 pm
I suggest this manual it has a lot of information about the Q-Jet..

http://www.cliffshighperformance.com/buy_book_2.html (http://www.cliffshighperformance.com/buy_book_2.html)
Title: Re: Quadrajet Carberator
Post by: popsthebuilder on May 23, 2013, 05:14:12 pm
Are you sure it's the carb? have a similar problem w/ mine every couple of months. No resistor for the coil. I still have points ignition. w/ out the resistor the coil goes out every couple of months. Even w/ choke problems it should at least fire.  If you have converted to hei then disregard.
Title: Re: Quadrajet Carberator
Post by: Jason S on May 23, 2013, 07:27:45 pm
If you have converted to hei then disregard.

1975 C-20 should have HEI from the factory.
Title: Re: Quadrajet Carberator
Post by: Steve341 on May 24, 2013, 06:21:51 pm
I bought a remanufactured Quadrajet. It is not a Rochester, its a Carter same thing though. I put the carb on, didn't take too long. Set the idle took it for a spin and it preformed just great. The next day I started messing with the air mixture screws. Yesterday my dad wanted to take it for a rip. So it is extremely windy and I'm packing a truck camper in the box so we had to open it up going into a 40 mph wind. Here we go. Sputtering yet again. Fuel pump seems to be fine, its not leaking or anything like that. Now what could be the problem? Reman carb on it, and its acting up again, but this time the carb is not leaking like the old one was.
Title: Re: Quadrajet Carberator
Post by: Steve341 on May 24, 2013, 06:24:44 pm
I bought a remanufactured Quadrajet. It is not a Rochester, its a Carter same thing though. I put the carb on, didn't take too long. Set the idle took it for a spin and it preformed just great. The next day I started messing with the air mixture screws. Yesterday my dad wanted to take it for a rip. So it is extremely windy and I'm packing a truck camper in the box so we had to open it up going into a 40 mph wind. Here we go. Sputtering yet again. Fuel pump seems to be fine, its not leaking or anything like that. Now what could be the problem? Reman carb on it, and its acting up again, but this time the carb is not leaking like the old one was.

It's Points
Title: Re: Quadrajet Carberator
Post by: Steve341 on May 24, 2013, 06:27:31 pm
On the plus I only have to pump it 1-2 times to start at cold instead of 30-40 lol
Title: Re: Quadrajet Carberator
Post by: 74 C-10 Shorty on May 24, 2013, 06:29:32 pm
I bought a remanufactured Quadrajet. It is not a Rochester, its a Carter same thing though. I put the carb on, didn't take too long. Set the idle took it for a spin and it preformed just great. The next day I started messing with the air mixture screws. Yesterday my dad wanted to take it for a rip. So it is extremely windy and I'm packing a truck camper in the box so we had to open it up going into a 40 mph wind. Here we go. Sputtering yet again. Fuel pump seems to be fine, its not leaking or anything like that. Now what could be the problem? Reman carb on it, and its acting up again, but this time the carb is not leaking like the old one was.
Sorry, Rochester and Carter two different animals, could be jetting but I'm betting on weak ignition...
Title: Re: Quadrajet Carberator
Post by: Steve341 on May 24, 2013, 06:48:11 pm
GM Contracted out Carter to produce the Quadrajet as Rochester could not keep up on demand.
Title: Re: Quadrajet Carberator
Post by: Steve341 on May 24, 2013, 06:50:03 pm
GM Contracted out Carter to produce the Quadrajet as Rochester could not keep up on demand.

I am leaning towards weak ignition as well. Sorry it is HEI there is no ignition coil at all. I never thought of ignition problems. I was about to order a new fuel pump, but I am told these mechanical ones either work or don't work or are leaking when they are failing. HEI, Wires, Plugs? What kind of cost am I looking at? Big Money for the HEI coil I bet
Title: Re: Quadrajet Carberator
Post by: 74 C-10 Shorty on May 24, 2013, 08:01:38 pm
GM Contracted out Carter to produce the Quadrajet as Rochester could not keep up on demand.
Yes that's true, but still two different animals nothing the same about them. ;D
Title: Re: Quadrajet Carberator
Post by: 74 C-10 Shorty on May 24, 2013, 08:11:18 pm

I am leaning towards weak ignition as well. Sorry it is HEI there is no ignition coil at all. I never thought of ignition problems. I was about to order a new fuel pump, but I am told these mechanical ones either work or don't work or are leaking when they are failing. HEI, Wires, Plugs? What kind of cost am I looking at? Big Money for the HEI coil I bet
Yes there is a coil, it's in the cap that's why it's bigger than a points distributor, now is this a stock factory unit?? I'm betting it is??, if I'm right that is the problem, factory units were made to go down the road at 2500 rpm for 200,000 miles not high rpm stuff and after 3500rpm they fall off, the cure is an aftermarket 50,000 volt coil and module that will give you a hot spark at any rpm no matter the load on the motor.
Title: Re: Quadrajet Carberator
Post by: Steve341 on May 24, 2013, 08:53:03 pm
I will go take a photo of the distributor and the Carter Quadrajet looks identical. All parts on the carter even have the same part number as the old rochester
Title: Re: Quadrajet Carberator
Post by: Steve341 on May 24, 2013, 08:53:55 pm
The Truck is a camper special, and I just am using it for that. There is a camper in the back surely it can go higher than 2500 RPM. So this cutting in and out has nothing to do with my tuning of the carb? The truck revs quite high with the rear end in it, geared to be a work horse not a speed demon meaning high RPM at lets say 60 mph
Title: Re: Quadrajet Carberator
Post by: Steve341 on May 24, 2013, 09:32:43 pm
I will go take a photo of the distributor and the Carter Quadrajet looks identical. All parts on the carter even have the same part number as the old rochester
Title: Re: Quadrajet Carberator
Post by: 74 C-10 Shorty on May 24, 2013, 09:33:48 pm
Oh it's possible the jetting could be off on the carb plugs will tell you that, but as you say it revs up pretty high that's because it has a 4:11 rear end gear(factory standard)and I'll guess you have about a 31" tire? that's around 3000rpm at 60 and will be ok at cruise but put a load on it at that speed and rpm increases and ignition will fall off, also the quality of the plug wires is a factor and the type plugs used, I may have missed it but did you do a complete tune up on this??.
Title: Re: Quadrajet Carberator
Post by: 74 C-10 Shorty on May 24, 2013, 09:37:10 pm
I will go take a photo of the distributor and the Carter Quadrajet looks identical. All parts on the carter even have the same part number as the old rochester

Looks like stock HEI, coil is is in the center on top.
(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=26124.0;attach=23063;image)
Title: Re: Quadrajet Carberator
Post by: Steve341 on May 24, 2013, 09:46:51 pm
I don't know if it has HEI ignition or Points. The distributor is quite large and I don't see a wire in the middle going to an ignition coil. I have a sneaking suspicion I wasted my money on the carburetor I never thought of an ignition problem.
Title: Re: Quadrajet Carberator
Post by: Steve341 on May 24, 2013, 09:51:57 pm
Should I start with new plugs and wires? I am going to return the old carburetor tomorrow to get my $50 core back. Should I pick up a set of new plugs and wires? The previous owner said they are 10-15 years old right now.
Title: Re: Quadrajet Carberator
Post by: 74 C-10 Shorty on May 24, 2013, 09:54:34 pm
I don't know if it has HEI ignition or Points. The distributor is quite large and I don't see a wire in the middle going to an ignition coil. I have a sneaking suspicion I wasted my money on the carburetor I never thought of an ignition problem.
Re read my post  you have an HEI, the coil is in the distributor it is self contained, the hump on the top is the coil, all it takes is a direct 12 volt wire to the unit, BTW did you check that???..
Title: Re: Quadrajet Carberator
Post by: 74 C-10 Shorty on May 24, 2013, 09:57:29 pm
Should I start with new plugs and wires? I am going to return the old carburetor tomorrow to get my $50 core back. Should I pick up a set of new plugs and wires? The previous owner said they are 10-15 years old right now.
Holy crap, 10-15 years old,LOL, yeah I'd say you need a complete tune up,lol, does this goes for the distributor too?, probably could use a new cap and rotor too.... Ok gotta go, be back in the AM.. :D
Title: Quadrajet Carberator
Post by: Steve341 on May 24, 2013, 10:14:12 pm
Lol I will pick up a set of plugs and wires and put them on tomorrow
Title: Re: Quadrajet Carberator
Post by: 74 C-10 Shorty on May 24, 2013, 10:17:01 pm
Lol I will pick up a set of plugs and wires and put them on tomorrow
Get quality wires and Autolite or NGK plugs..
Title: Re: Quadrajet Carberator
Post by: Steve341 on May 24, 2013, 10:19:25 pm
I popped off a wire. Sure enough Male on the distributor female on the wire. To be honest with you, This is the first time I've seen this. Always seen Male on the wire Female on the cap
Title: Re: Quadrajet Carberator
Post by: Steve341 on May 24, 2013, 10:51:46 pm
Could it possibly be the mechanical fuel pump? Can they somewhat work, or is the fuel pump a either it works or it doesn't work kind of deal. It does not leak.
Title: Re: Quadrajet Carberator
Post by: 74 C-10 Shorty on May 25, 2013, 08:12:08 am
It's not leaking and it's pumping fuel don't worry about it, one thing at a time just do a "complete" tune up first.
Title: Re: Quadrajet Carberator
Post by: Steve341 on May 25, 2013, 08:28:08 am
Thanks for the help buddy. I will let you know when I get the plugs and wires in and take er for a rip. I hope I wont be cutting 40 mph wind today
Title: Re: Quadrajet Carberator
Post by: 74 C-10 Shorty on May 25, 2013, 08:52:21 am
Anytime glad to help, don't forget with HEI plugs are gapped at .045.. And check cap and rotor I'm sure they need replacing too.
Title: Quadrajet Carberator
Post by: Steve341 on May 25, 2013, 04:56:23 pm
Best I could find was champion wires and Bosch platinum plugs
Title: Re: Quadrajet Carberator
Post by: Steve341 on May 25, 2013, 05:40:18 pm
These champions should be better then these Whitaker plug wires that's on it now. They look OLD wondering if they were from factory
Title: Re: Quadrajet Carberator
Post by: 74 C-10 Shorty on May 25, 2013, 08:16:26 pm
Couldn't find Autolite???, and here I thought I was in a hick town that didn't have anything,LOL, you have the small tapered seat plug right?, and nobody had 144's???, Bosh will do fine though.....

After 15 years under the hood anything looks old,lol, new ires should do wonders for it...
Title: Quadrajet Carberator
Post by: Steve341 on May 25, 2013, 10:11:38 pm
I googled these Whitakers. They are vintage 60s and 70s wires
Title: Re: Quadrajet Carberator
Post by: 74 C-10 Shorty on May 27, 2013, 10:35:12 am
Sooo, got er all tuned up yet?.. :D
Title: Quadrajet Carberator
Post by: Steve341 on May 27, 2013, 01:25:59 pm
Just put the plugs in. They all had oil on them lightly and black carbon deposits and #7 had real bad oil. Since I put my new carb on the cold idle sucks. How can I fix that
Title: Quadrajet Carberator
Post by: Steve341 on May 27, 2013, 01:27:08 pm
If I press the choke open with my fingers it runs not bad cold
Title: Quadrajet Carberator
Post by: Steve341 on May 27, 2013, 01:29:55 pm
Once it warms up abit it runs beautiful
Title: Quadrajet Carberator
Post by: Steve341 on May 27, 2013, 01:41:49 pm
Nope still there.
Title: Re: Quadrajet Carberator
Post by: 74 C-10 Shorty on May 27, 2013, 01:48:12 pm
Sounds like choke adjustment, is it electric or heat coil from the intake???..
Title: Re: Quadrajet Carberator
Post by: Steve341 on May 27, 2013, 02:05:55 pm
Heat coil. The hesitation is still there during accelerating
Title: Re: Quadrajet Carberator
Post by: 74 C-10 Shorty on May 27, 2013, 06:17:25 pm
Take that cover off and clean out the cavity and make sure the coil is not broken and clean, crud builds up in there over time and can make it non functional.... Is your timing right??, set total at 36* and all in by 2800-3000rpm, if it still stumbles then it's the accelerator pump, if it's 15yrs old  then odds are the carb could stand to be freshened up too..
Title: Quadrajet Carberator
Post by: Steve341 on May 27, 2013, 10:17:49 pm
I got a brand new rebuilt carb on it
Title: Re: Quadrajet Carberator
Post by: 74 C-10 Shorty on May 27, 2013, 10:23:49 pm
Well, like I said make sure timing is right first then go from there.
Title: Quadrajet Carberator
Post by: Steve341 on May 29, 2013, 07:39:42 pm
Timing. Now that is something I have no idea how to do.
Title: Re: Quadrajet Carberator
Post by: 74 C-10 Shorty on May 29, 2013, 07:48:47 pm
Timing. Now that is something I have no idea how to do.
Do you know how to use a timing light???..
Title: Quadrajet Carberator
Post by: Steve341 on May 30, 2013, 06:44:54 am
Nope. Never used one before
Title: Re: Quadrajet Carberator
Post by: 74 C-10 Shorty on May 30, 2013, 07:38:18 am
Nope. Never used one before
Well then I guess it's time you learn, I could type this out but it would take two pages and I don't have the time,LOL, this is a push for MSD stuff but it applies to any ignition, basics are the same and it is really simple but a huge factor in a tune-up..

http://www.youtube.com/watch?v=FZxsp7S7ZhQ (http://www.youtube.com/watch?v=FZxsp7S7ZhQ)
Title: Quadrajet Carberator
Post by: Steve341 on May 30, 2013, 02:56:20 pm
I'm going to buy a pump first before I start messing with that. I'm 99.9% sure it's a fuel problem.
Title: Re: Quadrajet Carberator
Post by: 74 C-10 Shorty on May 30, 2013, 06:35:39 pm
Whatever you want to do...
Title: Re: Quadrajet Carberator
Post by: popsthebuilder on May 31, 2013, 05:28:50 pm
Dude, a fuel pump is cheap, but so is a timing light. You will need one. They sell one at Harbor Freight that you can turn a dial on that represents the amount of advance you need. I suggest buying a Haynes/ Chilton manual for your truck at any auto parts store. The book will explain a lot of maintenance things including operation of a timing light. Directions also come with the light. Pull the fuel line off of your carb before the filter and have someone turn the engine over. Gas should shoot out for every revolution the engine makes. If it does then your pump is o.k. Just don't blow up. I'm sure someone is going to jump my *ss for telling you that but it will definitely narrow down the problem a little.       
Title: Re: Quadrajet Carberator
Post by: 74 C-10 Shorty on May 31, 2013, 05:54:14 pm
Pull the fuel line off of your carb before the filter and have someone turn the engine over. Gas should shoot out for every revolution the engine makes. If it does then your pump is o.k. Just don't blow up. I'm sure someone is going to jump my *ss for telling you that but it will definitely narrow down the problem a little.
I've done that several times, but I use a remote starter button never turn on the ignition so there is never a chance for a spark.. :D
Title: Quadrajet Carberator
Post by: Steve341 on June 05, 2013, 08:02:47 am
How do you time it? Turn the distributor while its idling at operating temperature?
Title: Re: Quadrajet Carberator
Post by: 74 C-10 Shorty on June 05, 2013, 09:10:40 am
How do you time it? Turn the distributor while its idling at operating temperature?
To set the initial yes with vacuum advance disconnected, to set the total you bring the rpm up to 3000 it should be all in by then.
Title: Quadrajet Carberator
Post by: Steve341 on June 05, 2013, 12:43:21 pm
Very interesting video. I have delco remy stock ignition. So it's the same then as the video?
Title: Re: Quadrajet Carberator
Post by: 74 C-10 Shorty on June 05, 2013, 12:56:11 pm
Yes, it's basic ignition tuneup..
Title: Quadrajet Carberator
Post by: Steve341 on June 05, 2013, 01:26:53 pm
Right directly under the water pump I see some teeth. Is that where I aim the timing light?
Title: Re: Quadrajet Carberator
Post by: 74 C-10 Shorty on June 05, 2013, 01:54:10 pm
Yes, clean the tab off and you'll see numbers stamped on it.
Title: Quadrajet Carberator
Post by: Steve341 on June 05, 2013, 10:12:52 pm
What number do I need to be on?
Title: Quadrajet Carberator
Post by: Steve341 on June 05, 2013, 10:38:22 pm
The oil on the dipstick smells like gasoline
Title: Re: Quadrajet Carberator
Post by: Irish_Alley on June 05, 2013, 11:24:22 pm
no no you look into the light. lol yes, but if its working right you will see a mark on the balancer. mark it with chalk will also help it stand out 0° will be on center. the smell is prob from blow by. i just change mine more often
Title: Re: Quadrajet Carberator
Post by: bd on June 07, 2013, 12:31:05 pm
The oil on the dipstick smells like gasoline

Pull the oil dipstick and put one drop of oil on the pad of your finger.  Does the oil form a smooth-edged drop that holds its shape, or does it track quickly out along your fingerprint?  If the oil drop quickly wicks and tracks your fingerprint, the oil is saturated with fuel and needs to be replaced along with a new oil filter.  For the fuel to be that saturated, replace the mechanical fuel pump, as well, because it has a perforated diaphragm. 

Simple blowby will not cause that degree of oil saturation over a short period of time as long as the PCV system is functioning; neither will a flooding carburetor.
Title: Re: Quadrajet Carberator
Post by: Irish_Alley on June 07, 2013, 11:16:57 pm
bd didnt know that maybe that could be one of my problems lol. but if the fuels not over flowing out the carb vents then how else would it make it to the engine?
Title: Re: Quadrajet Carberator
Post by: bd on June 07, 2013, 11:37:40 pm
Irish, clarify your comm.
Title: Re: Quadrajet Carberator
Post by: Irish_Alley on June 08, 2013, 01:08:27 am
the diaphragm on the fuel pump hows that affect the oil?
Title: Re: Quadrajet Carberator
Post by: bd on June 08, 2013, 01:35:02 am
You're correct in that excessively rich fuel delivery can wash the cylinder walls so clean of oil that the rings won't seal and some of the fuel, as blowby, will collect in the crankcase.  But this scenario generally describes a "gradual" contamination of the oil over many hundred to a few thousand miles.  In this scenario exhaust often smells intolerably rich.  The problem exacerbates if the engine runs only short distances and is never allowed to warm up, so that fuel collecting in the oil doesn't vaporize and burn via the PCV system.  Excessive maintenance intervals will also exacerbate fuel accumulation in the oil over the service life of the oil.  But, I don't think that's the case here.  It seemed the OP was describing a situation that developed fairly quickly.

A common cause of fuel saturation of crankcase oil is a ruptured rubber diaphragm in the mechanical fuel pump.  The diaphragm is the primary barrier between liquid fuel in the pump and the crankcase.  If the diaphragm tears, fuel is pumped directly into the crankcase.  Contamination occurs fairly rapidly.  This is where I think the problem lies in this particular case.  It's not an unusual circumstance.
Title: Re: Quadrajet Carberator
Post by: Irish_Alley on June 08, 2013, 01:40:14 am
see thats where you lost me about the diaphragm tearing. i always thought if it torn you would get fuel since there was no vacuum being created. never really looked at fuel pump never had to change one, like i said this could be my problem then. mine is the same one i had when i first got my 86 and that was prob close to ten years ago
Title: Re: Quadrajet Carberator
Post by: bd on June 08, 2013, 01:53:35 am
LOL - The diaphragm essentially is a flexible 'piston' that's pushed in one direction by the pushrod off the cam eccentric, then pushed in the opposite direction by the pressure spring.  As it moves back-and-forth it flexes.  A small tear may not stop the pump from working, but when the diaphragm is in the right position, it can open and bleed some of the fuel into the oil.  If the tear is bad enough, fuel will also leak through the vent onto the ground.  The fuel pump also has an oil seal.  If the oil seal fails, engine oil will leak through the vent holes.  It's a cruel world!
Title: Re: Quadrajet Carberator
Post by: Irish_Alley on June 08, 2013, 01:56:39 am
lol and let me guess another sypthom of this would be fuel draining back from the fuel filter when the engine sits for a bit of time
Title: Re: Quadrajet Carberator
Post by: bd on June 08, 2013, 02:05:14 am
That's always possible, but I'm more inclined to think it drains when the needle valve opens in the carburetor and breaks the seal against the seat.  It's kind of like drawing soda into a straw and sealing the end with your tongue.  What happens when you pull your tongue from the straw?  The straw empties to the level in the cup.  Using a fuel filter with an integral check valve may well solve that symptom if it's a concern.
Title: Re: Quadrajet Carberator
Post by: Irish_Alley on June 08, 2013, 02:20:43 am
not really a concern just dont know what causes it. dont have no other visible fuel leaks. and from what i remember it did it before and after the carb rebuild
Title: Quadrajet Carberator
Post by: Steve341 on June 09, 2013, 10:12:40 am
So after reading these posts I think my pump is bad. I changed engine oil and filter on my truck late summer early fall of 2012. I barely drove it since because its a pig on fuel. I maybe put 5-600 miles on it. I didn't pull the dipstick and take a drop of oil. I did get a new pump it bolts right on fine and what not. I removed the inline fuel filter that someone had installed. In guessing the only filter from the factory is the fuel filter located just past the fuel inlet on the carb. According to my Haynes manual anyway. Long story short I ended up reinstalling the old mechanical pump as the inlets are on the opposite side on the new pump and my hoses would not reach. Also I fiddled with the line that goes straight up to the carb and for the life of me I could not get the threads to start into the pump. If I extend the rubber line and connect to the new fuel pump with the inlets on the opposite side the old pump will that work? Also can I reuse gaskets ? I put the gaskets from my new pump on to reuse my old one as I had to scrape away the previous gaskets. Also Haynes manual talks about some kind of spacer  meaning the pump a gasket a spacer a gasket then connect to engine. Can you tell me what that is about? I do not have the spacer.
Title: Quadrajet Carberator
Post by: Steve341 on June 09, 2013, 10:23:56 am
All in all my oil is not dirty with that kind of mileage
Title: Quadrajet Carberator
Post by: Steve341 on June 09, 2013, 10:55:55 am
Rather cool day out here. And yup dropped oil on my finger from the dipstick and it runs down my finger prints and my finger smells like I've dipped it into pure gasoline.
Title: Quadrajet Carberator
Post by: Steve341 on June 09, 2013, 11:00:11 am
So what your telling me is my fuel pump is the cause of the stumble and hesitation? If I slowly bring it to 30 mph it will be fine there. If I floor it the motor cuts right out for a second then 4 barrel kicks in briefly and hesitates. Wants to stall and starts running rough when I stop at stop sign red light etc some of the time so I pop the automatic in neutral and rev it.
Title: Quadrajet Carberator
Post by: Steve341 on June 09, 2013, 11:04:03 am
Here is the pump I bought. All the same it's just got the inlets on the wrong side. It's a carter M60191 incase you cannot read the photo
Title: Quadrajet Carberator
Post by: Steve341 on June 09, 2013, 11:07:24 am
(http://img.tapatalk.com/d/13/06/10/ypute9us.jpg)
Title: Quadrajet Carberator
Post by: Steve341 on June 09, 2013, 11:10:15 am
Metal line connection to carb does line up like I said I cannot get the fitting started. Might try disconnecting at the carb slacken the metal line start the threads on the pump before I install it. Also when I reinstalled the push rod I used vasoline as it worked great to hold it up. Can I use it or should it be lithium grease
Title: Re: Quadrajet Carberator
Post by: farmerchris on June 09, 2013, 12:22:03 pm
sound like you got the wrong pump for your application,same style pump,but different application have the inlets and outlets in different directions, need to get the pump made for your truck
Title: Re: Quadrajet Carberator
Post by: farmerchris on June 09, 2013, 12:27:37 pm
http://www.rockauto.com/catalog/moreinfo.php?pk=296125&cc=1031971,   here a link to the right # for reference for your application.
Title: Re: Quadrajet Carberator
Post by: 454Man on June 09, 2013, 01:01:10 pm
I just went through this with my AC delco pump I got from rock.... I ended up getting a fitting and some ethonal proof rubber fuel hose.
Title: Re: Quadrajet Carberator
Post by: bd on June 09, 2013, 04:08:00 pm
Take the fuel pump back for the correct one!  Every aftermarket manufacturer copies ACDelco (the OEM supplier), so Delco supplies the preferred pump, though Carter should be satisfactory.  The Haynes referenced 'spacer' is actually a ~1/8" steel plate that sandwiches between the fuel pump and the block; two additional bolts have to be removed to remove the plate.  It's not necessary to remove the plate and, in fact, best to leave it alone, unless you're trying to resolve an oil leak from the pump mounting area.  You can reuse the gasket with a thin smear of silicone sealer as long as the gasket isn't torn.

Steel lines can be a pain, even with the correct pump in hand!  Using a 5/8" flare nut wrench, loosen the steel line from the carburetor.  On some vehicles, you also may have to loosen a clamp that secures the steel line to the engine block.  Don't take any more apart than you absolutely have to, to start the threads.  After you've installed the pump on the block, wrap two turns of Teflon tape around the threads of the line nut and then carefully start the nut with your fingers.  Before tightening the nut at the pump, wrap two turns of Teflon tape around the line nut threads at the carburetor end, and start it into the carb inlet nut.  Make sure both nuts are started without cross-threading!  Now tighten both line nuts using a flare nut wrench.  Be sure to back up the carb inlet nut with a 1" open-end and the fuel pump outlet fitting (maybe a 3/4" open-end) before cinching down on the respective tubing nuts.  By the way, the Teflon tape doesn't 'seal' the tubing threads, it just lubricates the threads so they will tighten adequately without distorting.  Effectively seating the line to the flare is what seals the connection.

So what your telling me is my fuel pump is the cause of the stumble and hesitation? ....

I'm not claiming this at all.  Reading through the thread you definitely had other issues that needed to be addressed - and you corrected them.  Now, it's time to correct this one.  Until the cause of the oil dilution is resolved and the oil and filter are changed you'll never be able to resolve your original complaint or even know whether it still exists beyond "excess fuel in the oil."

But, look at this experience from a positive point of view....  You have a CLEAN crankcase!   ;)
Title: Quadrajet Carberator
Post by: Steve341 on June 12, 2013, 12:03:20 pm
What was the link for that pump? Seems it disappeared
Title: Re: Quadrajet Carberator
Post by: bd on June 12, 2013, 12:37:28 pm
By application, your 1975 C20 w/454 calls for an ACDelco 40963 (https://www.acdelcodirect.com/products/air-and-fuel-delivery/fuel-pumps-and-related-components/40963).  The ACDelco 40963 pump appears similar to the image you posted, above. 

The Carter pump from Rock Auto is here:
http://www.rockauto.com/catalog/moreinfo.php?pk=296125&cc=1031971,   here a link to the right # for reference for your application.

If your original pump's line configuration appears the same, then either of these pumps will work.
Title: Quadrajet Carberator
Post by: Steve341 on June 12, 2013, 01:16:00 pm
I need to put longer rubber hose for the pump I got now to work. I can try installing it with longer hose. Can I buy 45/90 degree angles for this?
Title: Re: Quadrajet Carberator
Post by: bd on June 12, 2013, 01:30:59 pm
Fuel hose pretty much comes in straight lengths.  You need to be careful that the hose doesn't rub or chafe, and doesn't kink.  The best approach is to use a pump that's properly configured for the chassis routing and location of the existing steel lines.  Your local parts house should be able to help with fittings for custom lines.
Title: Re: Quadrajet Carberator
Post by: 80Chevy4x4 on June 13, 2013, 10:06:27 am
Here is a real carburetor website....it even has rebuilding video's.


 http://www.carburetor-parts.com/Free-Carburetor-Manuals_ep_274.html
Title: Re: Quadrajet Carberator
Post by: 74 C-10 Shorty on June 13, 2013, 10:34:32 am
Here is a real carburetor website....it even has rebuilding video's.


 http://www.carburetor-parts.com/Free-Carburetor-Manuals_ep_274.html
That's one of the better sites for information.
Title: Re: Quadrajet Carberator
Post by: Steve341 on June 14, 2013, 10:49:10 pm
Hey All, I got that pump to work after all. Took me about two hours to get the threads started with lots of prying on the line but its on. Took some priming to get it to start but its running with the pump I bought originally. Same thing happening with the hesitation. I was talking to my uncle about it, and he was asking how it is starting. I said the starter cranks over like nothing on a cold engine. If its warm and try to restart it, the starter lags abit. He told me its more than likely timing issue. So I was having a look at the HEI distributor, and I cannot find the distributor hold down bolt. He said its only one bolt that needs to be backed off just enough so I can turn the distributor freely but not too loose. Where is this bolt, and Haynes manual does not tell me the location of it. The manual also says refer to the vehicle emissions label under the hood, The label is gone. All in all, Where is this bolt that needs to be loosened so I can play with the timing and find the sweet spot. Please say I can get at this with a ratchet or a wrench. I do not have a distributor wrench.
Title: Re: Quadrajet Carberator
Post by: 80Chevy4x4 on June 14, 2013, 10:59:06 pm
Look where the distributor goes into the motor....you will see  almost like a hordeshoe piece of metal with a bolt going through it into the motor...that is the distributor bolt. 
Title: Re: Quadrajet Carberator
Post by: Steve341 on June 14, 2013, 11:00:29 pm
Back it off slightly with a ratchet and socket? Half Turn, quarter turn?
Title: Re: Quadrajet Carberator
Post by: Captkaos on June 14, 2013, 11:19:44 pm
If it is tight, it may take more than that, just remember to tighten it back down.
Title: Re: Quadrajet Carberator
Post by: Irish_Alley on June 14, 2013, 11:25:22 pm
and you have to use a wrench a distributor wrench would be nice
Title: Re: Quadrajet Carberator
Post by: Steve341 on June 14, 2013, 11:34:26 pm
and you have to use a wrench a distributor wrench would be nice

And That I do not have
Title: Re: Quadrajet Carberator
Post by: Captkaos on June 14, 2013, 11:40:53 pm
If you have a used wrench or a cheap one just heat is and bend it.
Title: Re: Quadrajet Carberator
Post by: Irish_Alley on June 15, 2013, 12:06:15 am
easy to make, cheap to buy
(http://i.ebayimg.com/t/Distributor-Wrench-Set-2-PC-1-2IN-X-9-16IN-3-8-DR-SET-never-been-Used-/00/s/MTIwMlgxNjAw/z/uygAAMXQhuVRR11S/$T2eC16F,!zQE9s3sqJPMBRR11R3Ydg~~60_57.JPG)
http://www.ebay.com/itm/PRO-VALUE-CARQUEST-39633-DISTRIBUTOR-CLAMP-WRENCH-/400498568149?pt=Motors_Automotive_Tools&hash=item5d3f932bd5&vxp=mtr
http://www.ebay.com/itm/K-D-Offset-Distributor-Wrench-1-4-3-8-No-291-Brand-New-Old-Stock-Made-in-USA-/330938313423?pt=Motors_Automotive_Tools&hash=item4d0d75eacf&vxp=mtr
Title: Re: Quadrajet Carberator
Post by: Steve341 on June 15, 2013, 08:35:29 am
Would this be my next step to work at the hesitation problem? Where do I want the timing set at on this 454? Don't forget I need lots of power, I don't care about fuel economy as I'm packing a slide in truck camper.

What I've done:
-Reman Quadrajet
-New plugs, and wires
-New fuel filter
-Removed inline fuel filter
-New mechanical fuel pump

Title: Re: Quadrajet Carberator
Post by: Steve341 on June 15, 2013, 08:41:12 am
Could it also be my mixture screws? What is every adjustment I can tinker with on the quadrajet?

Or is the engine nearing the end of its lifespan? I sure hope not
Title: Quadrajet Carberator
Post by: Steve341 on June 15, 2013, 09:38:28 am
Found the distributor bolt. Got er loose with a 9/16 regular wrench taking the air cleaner off. Warming up the motor now
Title: Re: Quadrajet Carberator
Post by: bd on June 15, 2013, 09:48:03 am
....

What I've done:
-Reman Quadrajet
-New plugs, and wires
-New fuel filter
-Removed inline fuel filter
-New mechanical fuel pump

Reminder:
The crankcase was full of fuel.  Don't try to adjust the carburetor until you change the oil and filter!  You'll never get it to run quite right until you do!  You'll also risk damage to the engine.
Title: Quadrajet Carberator
Post by: Steve341 on June 15, 2013, 10:28:57 am
One thing I forgot to mention is that if I floor it at idle it will hesitate sometimes as well. After I tightened the distributor I took off at half throttle. Zero hesitation. But going back I think it will start
Title: Quadrajet Carberator
Post by: Steve341 on June 15, 2013, 10:39:19 am
So what you're saying is a simple oil change will possibly resolve my hesitation?
Title: Quadrajet Carberator
Post by: Steve341 on June 15, 2013, 11:03:11 am
I uploaded a few videos to YouTube

http://m.youtube.com/?reload=3&rdm=mb32415st#/user/gunit6815?&desktop_uri=%2Fuser%2Fgunit6815
Title: Re: Quadrajet Carberator
Post by: 454Man on June 15, 2013, 02:44:12 pm
No you're oil has been diluted with fuel and needs to b changed.
Title: Quadrajet Carberator
Post by: Steve341 on June 16, 2013, 01:13:52 pm
Problem solved. It was simple and not even under the hood!
Title: Quadrajet Carberator
Post by: Steve341 on June 16, 2013, 01:14:39 pm
How many liters of oil does it hold? Does 6 sound about right?
Title: Re: Quadrajet Carberator
Post by: 454Man on June 16, 2013, 01:34:06 pm
What was the problem?
Title: Quadrajet Carberator
Post by: Steve341 on June 16, 2013, 01:42:08 pm
I switched from the left tank to the right tank and it's fine. I drove it for 40 miles 20 against the wind and I didn't notice the truck camper. My guess is dirty tank or it's partially blocked where the fuel leaves the tank.
Title: Quadrajet Carberator
Post by: Steve341 on June 16, 2013, 01:50:26 pm
It's workin fine 2 barrel and 4. Purrs like a muscle car
Title: Quadrajet Carberator
Post by: Steve341 on June 16, 2013, 01:53:03 pm
We headin out to the lake for a few days. Be interesting how it will handle the hills. Some pretty steep up and downs
Title: Quadrajet Carberator
Post by: Steve341 on June 16, 2013, 01:54:27 pm
Hope I can make em in 2 barrel mode to save fuel on them hills LOL
Title: Re: Quadrajet Carberator
Post by: 454Man on June 16, 2013, 03:44:29 pm
Good luck
Title: Re: Quadrajet Carberator
Post by: Steve341 on June 16, 2013, 04:59:06 pm
Thanks 454Man and everyone else for all the help. Without this forum I wouldn't know how to change a carb, fuel pump, etc
Title: Re: Quadrajet Carberator
Post by: Steve341 on June 27, 2013, 06:10:45 pm
After the camping trip here is my fuel usage. Total Fuel used: 34 Liters or 9 US Gallons. Total Distance driven 125 KM or 77 miles. Fuel Economy 8.5 miles per gallon. Sound about right for a 454? I was thinking it would get atleast 10. Not sure what the gears are, but it is a camper special 3 speed automatic and high rev.

So far so good and ZERO hesitation.
Title: Quadrajet Carberator
Post by: Steve341 on July 01, 2013, 03:03:45 pm
Well here we go. The problem returns.... 160 km from home
Title: Re: Quadrajet Carberator
Post by: Irish_Alley on July 03, 2013, 01:25:44 am
something i noticed with my 79 it would run crappy sometimes at idle then i decided to run 93 instead of 87 total different truck. runs like a champ now no more idle issues or hesitation once the carb warms up
Title: Re: Quadrajet Carberator
Post by: Steve341 on July 03, 2013, 08:18:39 pm
The highest octane we can get is 91. Ouch I'm getting 8 mpg on regular 91 isn't cheap
Title: Re: Quadrajet Carberator
Post by: Irish_Alley on July 03, 2013, 11:08:53 pm
meant 91 lol dont even pay atention to the numbers any more cause then you will see how much your paying lol