Quick and dirty: 53 chev 150 3 on the tree. was running good all of a sudden runs like crap. Won't idle at all without constantly pumping the gas. WTF? In depth: I have recently finished rewiging my 53 chev 150 and converted it over to 12V I've installed the pertronics ignition conversion as well. I had the car running well took it for a few spins around the block and all of a sudden it wouldn't run unless you kept pumping the gas (and the carb got very noisy, like the engine is sucking really hard). had my neighbour come over and he put his hand over the carb (total choke) and it started running perfect again. I figured it might have been a vapour lock (since the fuel lines were kind of all over the place). So I relocated the fuel filter and tidied up the fuel line a bit and called it good. drove it around town for a couple weeks no problems. On Saturday I was driving around and it started running like crap again. I limped it into a parking lot and called my neighbour to see if "cupping" the carb would make it run again. This time it did not. If I get the car "running" (more like stumbling) and I manually choke the carb down to about 90% it runs perfect. So I have come to the conclusion that the carb is not feeding enough fuel into the engine. So my question is what could be causing this and how the hell do I fix this problem. I really just want to drive the old girl.
Dirt in the fuel bowl I would say. Pull the top of carb off and check power valve and jet assy. to see if there plugged.
Thanks for your input Johnny, I'll pull the top off tonight and have a look. Any other sugestions while I've got the carb apart? I've heard to check the accelerator pump. How do I do this?
Although this booklet is a bit corny the information should help you inspect all systems: http://chevy.oldcarmanualproject.com/carb/UM900/abc14.htm
If you have to take that carb apart, I would rebuild it while I was at it. I just rebuilt the one on my 53 Chevy. Nothing to it.
Curt B, Thanks for that info. JSanford1974 I've got another carb that came with the car that I'm going to rebuild. the carb that is currently on the car was apperantly just rebuilt (looks new) but I'm unsure on the internals. I have a partial rebuild kit that came with the car as well so I think I will install what came in that kit into the carb that is currently on the car and if that doesn't work I'll have the other rebuilt carb to through on there. Then maybe once I have all the bugs figured out I'll through a duel carb manifold on, just to create a bunch more problems.
Find out the routing of fuel from bowl to the idle hole down near throttle plate. Just from memory, I think there is some sort of up-and-over in which the fuel goes through several kinks. You need to follow that path--it is likely plugged with a bit of crud somewhere. In many cases, you will be able to blast through sections from both ends with the wand on a can of spray carb cleaner...wear goggles!
Rule #1 on the old pot belly rochester carbs if it is a old carb the old pump rubber wont take the e 10 gas we have today, buy a new pump with a blue rubber seal on it , ! If it ain't blue,, ! Don't buy it,! Only the blue ones are made for e 10 fuel, that will get you gettin on down da road !
If you have not open carb yet just look down the carb and see if you have a good stream of fuel coming out of squirter (provideing that fuel to carb is all in order), if it squirts good then pump is good. If its open, look for shrinkage of the diaphram. If it does not fit firmly in pump bore then replace. If your that far into just get a kit and rebuild it.
Well it's not the accelerator pump. I swaped it out last night and it made no difference. I think I'm just going to rebuild the carb I have on my bench and see if that fixes the problem.
It could not have been directly a pump problem with your idle UNLESS pump rubber fell apart and bits blocked something else. Had a quick look at a B book...idle tube goes UP from bowl, across carb near top, then down to idle and off idle holes. Start with carb base, find the little holes, be sure they are open and hole feeding them is clear. Then follow that hole into middle casting and kee going unti you have gone up all the way, around a couple bends, and back down, cleaning and checking all the way. Have a good look at every passage and aperture you can find, check with powerful flashlight, blow carb cleaner through.
Remember, the thing is just three chunks of metal with a lot of holes in 'em. Assuming good float level, practically all trouble is one of those holes blocked with crud. Some fuel passages will also have sideways holes drilled into them, air bleeds. They are just about as important as the main fuel passage. Do not probe actual metering holes with anything hard enough to damage them. Suggest the nylon thigs that hold tags to clothing, copper wire unraveled from multistrand. If you find much crud, invest in a good inline filter with a lot of capacity.
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