Rottenchester carb sticking/flooding (PICS!)

[Burgersquatch]

So this 73 K10 I picked up.... the carb is flooding randomly. Well, the other day it ran out of gas. Should have had plenty but stalled rolling into the gas pump. Since pretty much this entire truck is original, I'm gonna go ahead and assume there's some crap in the tank. Going with that, something got past the one little fuel filter at the carb and got stuck in the float or needle somewhere. I'm thinking it flooded out what gas I had left because my gauge dropped out of nowhere (unless the gauges are bad - have dual tanks). A friend told me to tap it with a hammer or something and knock it loose. It worked and ran fine all day yesterday until the last trip home.

It started to idle funny while waiting for a left-turn. Shortly after that I could smell gas and knew it was stuck again. I argued with it through the neighborhood before it stalled as I rolled into the driveway. Checked under the hood and yeah, it was wet. Since it was dark outside, I left it til this morning. Tapped on the carb around the fuel inlet and float bowl like I did the other day and it started up fairly ok - not like when the block is warm, but it cooperated. It sputtered a little gas out of the pump rod hole (where it was straight spewing the other day at the gas station).

Supposedly, someone at an off-road shop took the carb apart, cleaned this and that, adjusted the float and replaced some secondary rod. I'm not trying to doubt that this work was in fact, not done... but seeing as I wasn't charged for it (bought a battery tho), it's possible they did nothing.

The carb is a Rochester 4bbl, rebuilt by Holley (I don't know the model #). It was put on this truck about 9-10 months ago. The guy I bought it from said it would stick on occasion but not frequently. He also stopped driving this truck after he got a newer Toyota 4Runner. He said it only happened a couple times but I don't know the time frame. This is the 3rd time it's happened to me.

I'm considering splicing a secondary fuel filter in the line between the tank selector valve and the engine-mounted pump. I have not yet checked the fuel filter I have now, I should, I need to, just don't have any tools or time right now. Oh man, do I need tools. I really can't afford a new carburetor right now, or probably for quite a while. There's no way to even try to warranty the carb I have, so I'm kinda just stuck messing with it. Really just looking for some advice on how to deal with this issue...

[bd]

Welcome form California.

Install the in-line fuel filter between the pump and the carburetor - not on the suction side of the pump.  The inlet needle may be sticking because of the way it's installed, if it "hooks" onto the float.  You may also have a float that is heavy with fuel if it's composed of closed cell composite material.  There are other possibilities, as well, but all should be correctable at low cost if you can do the work yourself.

[bake74]

     With a small set of screw drivers and wrenches, a rebuild kit, and some patience, for around $100.00 you can rebuild it yourself.
     If you can not afford that right now, get on the Internet and copy off instructions on how to take it apart and clean it.  Find a friend with a basic set of tools and you will be set.
     If you keep messing around with it you will probably only frustrate yourself and possible end up doing more harm in the long run.
     It is not hard to take one apart if you follow instructions and take your time.
     Good luck in whatever you decide.

[Burgersquatch]

Thanks for the reply and tips. I was thinking an in-line filter before the pump would help keep the pump clean but I'll do some more research for I go and do anything.

I haven't gotten into this carb for myself and since I need this truck for daily transportation, it's difficult to find the time to dig into it and get it back on without causing a problem myself. I realize it's probably easier than I'm thinking, and call me a noob or whatever, but I'm a little apprehensive to take my only ride "off the road". I have one friend here who knows old vehicles but we work at the same place, which makes it a bit tricky for both of us to have the same day off and we can't really mess with it at work. It's also been pretty cold and windy here (Tahoe). Rained all day today and will probably have snow by the weekend. There is a garage at the house here that I could probably have access to on occasion (housemates park in it). Not many tools here, I'll have to hit up a thrift store or something.

Didn't make the parts store so I don't have a replacement fuel filter yet.

Earlier today, I went to work and it acted up around the corner from the house and stalled. Got out, tapped the carb a bunch and managed to get it going before too long. Ran fine on the 20min drive to work. When I got there my boss needed a ride down the road, started and ran fine, I waited in the truck with it running and it was again fine. Left work ok, stopped for groceries and dropped off a friend and was fine the whole way home. Then, as I pulled into my neighborhood, downshifting from 4 to 3 (4spd manual) with not really revving high at all, as I gave it a little gas to continue moving along, it chugged and acted like it was gonna get stuck and stall. I kinda "pushed" through it, argued at the stop sign but got it into the driveway without stalling. After the stop sign/left turn it seemed fine and didn't sputter in the driveway when I pulled in.

[bake74]

     Here's a thought.  First pay attention to what bd said. Do not put the filter on the suction side.
     You got any junk yards up there ?  I have been to Tahoe a lot but don't get around to everywhere.  If you can get a carb off a junker and rebuild, then it is only 4 bolts and hoses to put on, 1 hour tops with the fine tuning. 
     I am not going to presume your situation for a second with money and what, but take it from us who have 30 plus yrs working on vehicles, sometimes it is better to get a second one and replace the first one if you can not afford your vehicle to be down.
     You might have to save and look around for awhile but it would be worth it.  If you have absolutely no access to another carb, I am not too far away, I bet I could find a used one around and send to you. 

[Burgersquatch]

Good call on the spare carb, pretty smart thinking. I'm a tattoo apprentice (Cosmic Creations) and on a pretty tight budget. I'm pretty busy between keeping the shop happy and trying to pick up side jobs for whatever money I can get. So far, so good... but I'm gonna have to do some crunching and see what I can come with that will work with my situation. I haven't had time to get into anything yet and the weather has been pretty miserable so I can't even tinker during downtime at the shop.

Thanks so much for the info guys, really helps my stress levels knowing there's someone who knows what they're doing.

[Burgersquatch]

I'm wondering if the idle is set too low, if that would cause this problem? I seem to be having daily issues with this thing.
I'm pretty much in the habit of tapping the carb before I start the truck, before I hit the road, or both.

It's been starting ok, sounds like the auto-choke runs a bit high so I push the pedal a little and the rpm's drop to normal idle. Although it seems the idle is a bit low because this is when it'll chug and stall if I don't hold the pedal slightly. After it warms up a bit, it usually idles fine. Add the heater or defrost and you can hear/feel the system work a bit more. Turn on headlights and the power drops a little more, to the point where I feel it somewhat necessary to put my foot back on the pedal. Should I try increasing the idle speed?

It seems that somewhere, roughly half-way, on my 20 minute drive to/from work, that if I have to stop at a red light, it starts to sputter and wants to stall. I put my foot into it and "argue" with it through 2nd, which is pretty much my starting gear since 1st is granny gear. Once it's got some rpm's and is cruising down the road it's fine. At about 40-45mph in 4th (4spd), the motor/exhaust note seems to oscilate (kinda go up and down rhythmically). With all this sticking/flooding going on, it would make sense that the plugs/points got fouled. Still being tool-less, I haven't checked anything. The distributor cap seems to be a little noisy, kinda rattly at times... think it's got issues?

When I first got this truck and started with the carb, there was a cable hand-tied around the linkage for the vacuum side. It was tied in a way to keep the front flapper open and a rod pressed into the vacuum diaphragm. It was removed a while ago, after the first time I got stuck in a parking lot, should I put it back?

[Jason S]

It sounds like you may have several issues going on. You shouldn't need to adjust the carburetor idle (screw on driver's side of carb) if it is idling fine when the engine is warm.

I'm not certain, but when referring to the cable and  "front flapper" it sounds like someone tried to disable the choke mechanism by tying the vacuum choke pulloff closed.  It also sounds like you may have a partially working fast idle mechanism and/or other issues. There should be a fast idle and intermediate idle with the choke operating correctly.  The idle settings on the choke can be adjusted. One common issue with the choke is  the choke thermostat isn't working properly.

If you still have the factory Q-jet on your truck there should be a little metal box (thin sheet metal) attached to the intake manifold beside the carb on the passenger side. It should have a metal a rod coming out of it that attaches to the choke mechanism on the carb. That metal box has the choke thermostat spring inside.   If it is not as above, take a photo of the passenger side of the carb. Other models of Q-jets had electric or hot air thermostats.

If the thermostat is not working properly the choke mechanism isn't going to open or close as it should. Same thing goes with the vacuum pulloff.

[Burgersquatch]

It sounds like you may have several issues going on. You shouldn't need to adjust the carburetor idle (screw on driver's side of carb) if it is idling fine when the engine is warm.

I'm not certain, but when referring to the cable and  "front flapper" it sounds like someone tried to disable the choke mechanism by tying the vacuum choke pulloff closed.  It also sounds like you may have a partially working fast idle mechanism and/or other issues. There should be a fast idle and intermediate idle with the choke operating correctly.  The idle settings on the choke can be adjusted. One common issue with the choke is  the choke thermostat isn't working properly.

If you still have the factory Q-jet on your truck there should be a little metal box (thin sheet metal) attached to the intake manifold beside the carb on the passenger side. It should have a metal a rod coming out of it that attaches to the choke mechanism on the carb. That metal box has the choke thermostat spring inside.   If it is not as above, take a photo of the passenger side of the carb. Other models of Q-jets had electric or hot air thermostats.

If the thermostat is not working properly the choke mechanism isn't going to open or close as it should. Same thing goes with the vacuum pulloff.

This carb was rebuilt by Holley, purchased and installed by the previous owner. I'll see what I can do to upload a picture.
Thanks for the info.

[Burgersquatch]

I'm on my android phone, let's see If these pics work...

[Burgersquatch]

I'm on my phone, let's see If these pics work... again

[HAULIN IT]

Your missing the choke mechanism from the side of the carb. The flap set-up is there, but you need either an electric coil unit or a hot-air set-up on the intake (the Blackish pad on the intake under the carb in your last picture with the 2 holes in it) to control the top flap. It would explain the wire tie holding the pull-off...it would keep the flap from going shut.
I'm guessing this is much of your problem, flap flops shut, floods out engine, ect. Lorne

[bd]

The images show what Lorne is saying. 

Image number...

• The choke parts you're missing...
• The flat rectangular manifold surface inside the red circle is the choke thermostat mounting pad.  The thin purple line points to the slot in the choke linkage for the "clip" end of the metal rod.  (Ignore the red arrow).
• An approximation of how the missing parts should be installed - the choke thermostat is screwed onto the mounting pad; the end of the rod with the long 90° bend hooks to the choke thermostat coil; the end of the rod with the short 90° bend hooks through the 'slot' in the choke linkage and is held with the 'clip;' and the 'stove' snaps down over the choke thermostat to hold the rod in place and help trap heat around the coil, so the choke will open properly.

[Burgersquatch]

Anyone happen to know part #'s ?

1973 Chevy K10 350 V8, Rochester Quadrajet - unsure of model, here's a photo of some numbers i found:

[Jason S]

The model should be a Rochester Quadrajet.  I don't have any books right on hand at this moment, however according to http://www.recarbco.com/technical/rochester/qjet.html, http://www.cliffshighperformance.com/tech_carb_ID_2.html and http://www.carburetion.com/quadnumber.htm your carb is a 1973 Chevrolet Q-jet, 49-states emission (i.e., non-California) with an automatic transmission produced on the 306th day of 1972 (i.e., 3062). The QM should be a production code.