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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: roofdoctor on January 05, 2013, 04:07:09 pm

Title: new carb?
Post by: roofdoctor on January 05, 2013, 04:07:09 pm
I have an 84 c10 ,305 (H).  I have pulled the carb, not sure whether to put in an edelbrock 600 or get a rebuild kit.  (Rochester4bbl#17084226).  I do not need performance really, it is a work truck, but I put alot of miles on it. With a rebuild, I can put everything back how it was; but I have to rebuild a carburetor :( .   Will a new one require any additional brackets or spacers or anything? Also, even though I have a manual, and have been studying this problem for  week, I am still fairly clueless about which vacuum hoses are which, and where they go if I put in the edel.  and how to hook up the electric choke?  A new rochester is out of the budget.

Thanks in advance for any advice/help
Title: Re: new carb?
Post by: 81_Chevy on January 05, 2013, 09:07:45 pm
for the new carb you would have to get an adapter plate to go onto your stock manifold to fit the edelbrock, you would have to hook up the electric choke (if it doesnt already have one). IMO if you want the new carb buy it. but if your streched on money go down to the local auto parts store and get a rebuild kit $100 ish. if your not sure how to take it apart and stuff a good trick is to setup a video camera and take the carb apart slowly and then if you get stuck on the rebuild just look back on the video.

on my truck im just putting a new carb on it cuz im sick of messing with my q jet trying to get it tuned.
Title: Re: new carb?
Post by: Captkaos on January 06, 2013, 02:12:22 pm
I would rebuilt what came on there.  That is a R4-M4ME Qjet (Electric Choke on the side).  A rebuild kit is less than $30.  There is a post on here recently showing how to rebuild one..
Title: Re: new carb?
Post by: roofdoctor on January 06, 2013, 10:09:45 pm
thanks guys. I am leaning toward rebuild, heard that from a buddy of mine too. will search for that post
Title: Re: new carb?
Post by: roofdoctor on January 07, 2013, 11:14:39 am
anyone have any tricks for replacing vacuum hoses? Easier when warm?
Also, what if the idle solenoid is bad- can it be bypassed?
Title: Re: new carb?
Post by: Bigred85 on January 07, 2013, 03:57:50 pm
Try (National Carburetors) good reputation. I just got a professional rebuilt quadrajet for under $200. Runs like a top.
Title: Re: new carb?
Post by: roofdoctor on January 07, 2013, 04:17:13 pm
I found them online, that is a good recommendation but I  already took it to a local company. Ill see how they do. Also I found that 5/32 vac line is alot easier to work with than 7/64 in this case, lol
Title: Re: new carb?
Post by: 81_Chevy on January 08, 2013, 01:40:02 pm
when i replaced my vac lines i just went down to  O'Reilly's and got like a 4 ft roll of some and cut them to the same length as the old ones and replaced them. what do you mean by the idle solenoid? ive never heard of this before.
Title: Re: new carb?
Post by: roofdoctor on January 09, 2013, 09:12:27 pm
there is a small cylinder mounted on a bracket in front of the throttle linkage with a 1-wire connection and an adjustment screw.  Two sources including Haynes say this is how to adjust the idle speed.   I have been told they tend not to function by this time.  I guess I will have to try it out when I get the carb back on. 
Title: Re: new carb?
Post by: jaredts on January 09, 2013, 09:50:27 pm
It sounds like the idle compensator.  If it is it only kicks in to bump up your idle when the air conditioning kicks on.  You would adjust it by turning on the a.c. and adjusting the idle speed.  The idle speed screw should be easy to spot because when you open the choke flap and move the throttle the throttle bracket will rest on it.
Title: Re: new carb?
Post by: roofdoctor on January 10, 2013, 08:14:06 pm
I guess that explains why that other guy called it an "a/c step motor" .  Thanks for clearing that up.
Title: Re: new carb?
Post by: jaredts on January 10, 2013, 10:34:17 pm
Step motor is definitely not a good description of that device.  Its just a solenoid with an adjustable stop.  A step motor is a rotary motor with a certain number of steps per revolution used in printers and small motion control machines. 
Title: Re: new carb?
Post by: roofdoctor on January 14, 2013, 09:29:27 am
Well with help from you guys and this site, I got it put back together.  While I had the carb off and was replacing the vac lines, I installed new valve cover gaskets as a first step in stopping oil leak(s?).  Replaced EGR and PCV valves.  And did a ton of cleaning, being careful to keep
distributor covered.  Still not gotten half of the oil off though. 
Now, it starts rough- always did in the cold- but then it winds up and up and up, blows a lot of smoke, and quits.  Anyone got an idea?
I've had this truck for a year, have been using 20/50 per recommendation of guy I bought it from, which is maybe bad, idk, this time I used 5/30.
When I pulled the valve covers, everything looked...well...uh...black...
Some of the smoke seems to be coming off the catalytic converter, hard to tell on account of the oil burning off the surface of the exhaust. I believe everything behind the exhaust manifolds is new-ish.
Title: Re: new carb?
Post by: bake74 on January 14, 2013, 06:40:12 pm
     If by cleaning you mean you were washing the oil off and it was running down to the ground, then it is going to smoke a lot until you finish cleaning, or it burns it off.
     As far as the idle going up and up, are you sure you have no vacuum leaks ?  The other idea is distributer, ( I know you said you covered it ), did you check to make sure it is dry inside ?
Title: Re: new carb?
Post by: jaredts on January 14, 2013, 08:19:31 pm
Have you hooked up the choke wire to the side of the carb.?  Properly set the choke?  Does the idle wind up in a matter of seconds or minutes?  Black smoke?
Title: Re: new carb?
Post by: roofdoctor on January 14, 2013, 09:32:34 pm
choke wire is set.
smoke is white/grey
winds up in minutes not seconds
today I got it to run and took it to the place that rebuilt the carb, they adjusted the idle, seems to work okay now.  He said the vacuum advance tends to go bad, told me how to check it.
Still have not managed to adjust the tv cable, tho tried the directions in the tech pages here; it is still slack, and
I am not sure what it does.
It runs a bit rougher than before it quit, and drives more aggressively, and it lurches when shifting gear @ about 20 mph
still have to pump the gas a little sometimes to get it started
BUT IT WORKS! HAHAHA!  Felt pretty good putting all the tools and ladders back this afternoon. Plus apparently I have a new hobby now. Wife thrilled.