C-60 Truck....GM Carb....

Well not a tractor...but related to.... it has 4 wheels Question...remember this carb anyone? Was new 3 yrs ago and only use this truck once a year; starts good and idles BUT when I push on the pedal it falls on its face and will die...no acceleration. When I look in carb and move linkage it does spray two streams of gas..... need to rebuild again? Thanks.

Might not be the carb, Might be the advance on the distributor.

What happens when you flutter (quickly move fuel peddle up and down)? This will test if its a carb issue, or spark (& advance) issue. Accelerator pump(s) should put a bunch of fuel into the intake, and it ought to accelerate. If it does, and then dies as soon as you stop fluttering, its likely a main jet (clogged) issue. If even with a bunch of fuel from the accelerator pump it still doesnt rev, then Id think its likely a timing (advance) problem.

Remember them well!

Once assembled one without looking at it prove a point to a doubtful customer! LOL

Might want to check the points gap before going any further, closed up points can also cause off idle stumbling. Check the spark quality at the plug end of a couple wires. Be sure the centrifugal advance is free and the springs are intact.

The accelerator pump needs to deliver fuel under all opening speeds. Even ever so slowly opening the throttle it needs to at least dribble fuel, and it needs to begin to pump as soon as the throttle comes off the idle stop, no slack in the linkage.

Do you remember if the pump was rubber or leather? Probably rubber, but if leather, take it out and rub some oil into it to freshen it up. If rubber it should still be good as new as it is.

There may be some residue in the bowl from sitting, a good cleaning, even if you just ease the top off and spray it out, poke out the jets with a wire, clean the idle tubes (small tubes hanging down from the bottom of the venturi assy).

Have you checked the fuel pump output? It may only be delivering enough to make it idle. And the fuel filter, you should be able to blow through it with minimal restriction. If it has the spring loaded plunger, pull it out and discard it, but keep the rubber gasket in place. Be sure the rubber hoses at the pump and at the tank are good, not cracked and sucking air.

Is the thermostat installed and working? A cold engine will be cold natured.

(quoted from post at 10:44:24 06/17/21) Well not a tractor...but related to.... it has 4 wheels Question...remember this carb anyone? Was new 3 yrs ago and only use this truck once a year; starts good and idles BUT when I push on the pedal it falls on its face and will die...no acceleration. When I look in carb and move linkage it does spray two streams of gas..... need to rebuild again? Thanks.
<img src=https://www.yesterdaystractors.com/cvphotos/cvphoto92132.jpg>

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ooks like a Rochester 2GC. Very reliable carb. Sounds like something going on with the accelerator pump. Yes, you're going to need to take the top off and see what's going on. Very strange that you're getting two streams of gas and still have an off-idle stumble. Look for vacuum leaks.

One more thing you might check is the spark. In a past life as a parts man, I remember GM having a problem with their coils. It acted like a carburetor problem, but was actually a weak spark. At that time we sold a high output Echlin gold coil. Many times a new coil and wires cured the carburetor problem. Make sure you are getting a good blue spark at the plugs.

timing is 4 degrees BTC..... dwell is 30...... new plug wires...I will remove carb and open and check things out...then a
coil...thanks guys!

i agree on checking the fuel pump, more likely than the coil. should have a full flow that shoots 3 ft, if its a dribble its toast. plus there is a pressure test for them, think 3-4 lbs, but i just go by the flow test.

Looks nasty inside - mostly an aluminum look in the gas in the bowl....and is there a ball in the pump chamber or just the
spring? Thanks.

yes ball is the check valve.

The early ones had a ball in the pump chamber and under the spring.

Later ones did away with the ball in the pump chamber. If there is no round hole under the pump, then no check ball.

this was a rebuilt carb two yrs ago from the Internet....so I assume no ball is the way it should be....? Thanks

(quoted from post at 12:53:42 06/17/21) this was a rebuilt carb two yrs ago from the Internet....so I assume no ball is the way it should be....? Thanks

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If it is not the points or carb,, the primary wire from coil to points may have an intermittent open when the vac advance moves the breaker plate as you open the throttle. broken wire inside the insulation, inside the distributor. test by operating the vac advance with vacuum tester.

A carb that goes lean upon opening throttle (plugged main jets) will pop back through the carb.

adjust the choke,if it is standing open at start like it uis now that is the problem.

choke should not be shut when it is 104 outside

Ok...my distributor does NOT have a vacuum advance...no dashpot with a hose on it; all it has is a sending unit with a wire;
and there is no wire on it; and a dashpot of some kind but no hose anywhere.

I have worked on this for 7 hrs today; my feet hurt from standing on the bumper! I cleaned it out and have put it on three times
now and it starts and runs BUT after 30 secs it starts running gas out the top and is flooding and dies. What the hell did I do? I
have done it over 3 times and all looks good inside! I tried to find a new one but I guess they dont make them anymore for these
old trucks; if I did find one harvest will be over by the time it gets here! WHat a mess. thanks for all the help!

that distributor has a governor, not a vacuum advance. and if its flooding you got junk in the needle and seat. so that means the pump must be good as you did not say if you checked it. plus if it was not flooding before that means the float should be good unless something happened to it. also did you check the float level??

well at room temperature you turn that black dial so the choke plate just closes. then tighten the 3 screws.

well if you were close i would do that carb free for you. hard explaining stuff and when people dont understand what your talking about or the order they think your just being a smart asz. but no that not the case with me i like as much info as possible and ask questions for a reason. plus another thing finding carb mechanic's now is becoming obsolete.

will put it on for the 4th time this morning- float and level are fine...I blew needle and seat out again...thanks....so that small dash pot is a governor of sort?

yes I know....thanks

I understand its quite simple...just not my day! than when I went out this morning I find I had left the key on this truck all night....hmmmm