The Stovebolt Site Forums The Shop Area Engine Shop carb ? engine dies fuel starve?

My 1954 Chevy Truck 3100 with 235 engine dies out while driving. Warmed up. Happened today clutch in, starved. Let it sit. Started. Went 1 1/2 miles died to a coast to my driveway. Let sit ten minutes started again. Reved up no hesitation. Before I started checked the fuel filter bowl was 1/2 full of gas, opened the carb butterfly valve and saw puff of smoke - probably just just didn't see the gas. What gives? Please help.

D.Lee needs help

Could be a lot of things. fuel pump, fuel filter, blockage in the fuel line. These models quite often have trash that collects in the fitting right under the fuel tank. Loosen the fuel line on the suction side. Fuel should gravity flow out of the tank. Another thing that can cause this is a bad coil. When the coil heats up, the windings expand and short out. If you eliminate fuel, try a different coil and check other things like an intermittant ignition switch or a primary wire that is rubbed and grounding.

Thanks for the reply. More info. Fuel tank was cleaned out and re-installed recently. New fuel filter, new fuel lines, new coil. I'll look for a wire, though I think it is fuel related. Which is the suction side of the fuel line? The one that goes from the tank to the pump or the pump to the carb? Does the fuelpump go out intermittantly?

Get your truck out and go for another drive, if it dies, pull over as fast as you can and get out under the hood to check for fuel in the carburetor. If its dry, you are chasing a fuel problem, if it has fuel, start looking at the ignition.

Suction side of pump is line coming from the tank, pressure side is going to carburetor. A weak pump could cause this when the fuel demand is high, but even a weak pump will keep up with stop and go easy driving. Most pumps work up to the point of death, then they are done, it would be rare for one to be intermittent. The fuel line from the tank is most likely the problem. Its a small opening at the bottom so if anything gets loose in the tank it will end up at the opening. Just to check, loosen the line at the fuel pump (suction side) and let the fuel run into some cans, let the whole tank drain out. You can then re-clean the tank or inspect it better, it would also be a good time to install a temporary filter at the base of the tank. Fuel pumps have very little suction power and don't like to pull fuel through filters so its not really recommended, but in cases like this where you need to check for trash in the line, it will be OK. You can remove it once you are sure its clean.

You said the tank was cleaned and reinstalled, how was it cleaned? The new fuels of today are excellent cleaners and will loosen a lot of trash in a old tank!

Keep us posted, Joe.

D.Lee,

As you do your detective work, keep in mind that a float that hangs closed for whatever reason will starve your engine too. This doesn't happen too often, but it's worth keeping on your shopping list.

Stuart

Like crwenweldge said, heat will expand things (like the coil) and cause an open circuit.

I have a hard time feeling that a gas & carb problem is going to be that consistant on AND off. I would think a gas problem is usually on OR off.

Is this a new build? Is the timing right on?

I had a fuel starvation problem a while back cause my filter was full of junk. I could drive a ways on the highway and then it would die. I couldn't just hit the starter after sitting 10 min. and it would fire up. I would have to crank it for a while till more fuel entered the carbs. So if your rig is starting right up I wouldn't think it to be fuel related. I'm leaning more towards the coil.

do you have an add on electronic ignition?? the reason I am asking is that I had a mallory electronic on mine.. I had an off and on problem like yrs.........

mine was because of
needing to replace

this

Boy, what great timing !!!! I am working on a friend's 1954 3100 with the same problem. He knows three guys with similar trucks and they ALL have the same issue. This is a completed decent "driver" restoration, rebuilt engine, redone wiring, etc., etc. The carb is a generic reman, and I have not figured out what carb it is supposed to be. It has two floats on a common arm, and the float bowl wraps around the single throat. Oh, manual choke. It has both a "rattle cube" electric fuel pump and a mechanical as well, not a setup I like very much. There is an in-line filter at the mechanical pump as well as the in carb filter. His description is that it will stop running after a while, at which time he can crack the fuel line at the carb, and fuel spits out. Not conclusive to me. He says that if he pumps the throttle at that point, no fuel is delivered! This truck has been converted to 12 volts, and there is a ballast resistor on what I am told is a new 12 volt coil. The tank was cleaned.

So ................. I guess I need to start from scratch. Any suggestions? I'll get a kv reading on the ignition, check fuel pressure with the electric pump removed, make sure there is no junk in the line at the tank, etc. This should be a fun (?) puzzle.

edit; I figured out that the carb is a Rochester. Anybody know the float settings?

I've got an old 48 that does this intermittantly. The float some how sticks, shutting the fuel off and it dies as soon as the bowl runs out. A few light raps with a hammer handle gets it free and it may be good for months, may die again the next day.

Try removing the fuel line at the pump, tank side, and blow back towards the tank. Most of the time it's the problem,
Scott

MAN...my 54 did the same thing and did I need help and got it from some very nice guys on this forum. A couple of our problems were the rubber fuel hose coming from the gas tank had a kink/rotten in it and would suck shut. After the engine starved it would allow gas back to fill the bowl and start the cycle all over again. Coil was changed along with condenser and a new positive Batt. cable and the ground was checked. A new all metal Napa in-line fuel filter installed after the pump (not over the manifold) and a filter sock installed in the gas tank. The Rodchester B carb was re-built and off we went..T/C Steve

And.............dont forget to check the needle and seat in the carb. I had the same prob in my old 54 1 ton flatbed that would crap out whenever it felt like it. A teeny lil piece of crud would get stuck in the float/needle/seat assembly and drive me NuTs!!..!!..!.!

Even a new fuel filter can clog quickly after a fuel system cleaning. Might want to think about a new filter again.

DING DING DING DING !!!!!!!!!!!!!!!!!!!!!!! We have a winner. I pulled the carb to see if there were float and needle problems. There was some dark matter on the threads of the fuel inlet so I pulled the adapter from the carb top. The little filter was absolutely packed solid with more of that matter. I knocked it out of the filter to let it dry. Clearly, it was residual media that had flushed out of the tank from its cleaning during the restoration. Should be back on the road today with a new filter in the carb and an inline filter aft of the fuel pump. Thanks for the help.

Note to a previous posted with the 48. If blowing back through the fuel line clears the flow, a) try a new cap, and b) you may have stuff gathering up at the supply point in the tank.

What side should the fuel filter be on? Pressure or Vacuum?

put the filter on the pressure side..between the pump and the carb. The pump can push a lot more than pull. Your experience is more proof that the $125 I spend on after market tanks on all my old toys is worth it. 50 year lead and stale gas sediment is hard to get rid of.

Gee you guys, thanks for all the pointers. Sure is a lot of good information. I'm going to start with the fitting on the hose from the tank, drain some gas, blow back into the tank and a get a new fuel filter. If it stops on the road again I'll check the carb for gas.If it dies again I'll come back to try something else offered in the forum.I'll keep you posted as to what happens next.

So - I changed the fuel filter, started the engine - it idled for five minutes and died. I touched the coil and it wasn't warm. Had trouble starting again, then it started and died. I took the top of the carb off - the bowl was full. I think you're right about this not being a fuel problem. It is a new build. I think the timings right on - it was just checked. I'll check it again. Thanks for the pointer.