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Just bought a 1972 base model coupe with 41K original miles. It is a numbers matching car. It was stored for 12 years with gas in the tank and this caused rust to get in the fuel system. After having stalling problems, I replaced the tank and fuel lines. The car drove great for a few weeks, but now stalls when th engine is warm. Any ideas what I should be looking for? Any more info needed?
The first thing I would do is a complete tune-up if you haven't done so already. If that doesn't solve the problem, you will probably have to get in to the carb. With fuel sitting in the carb for that long, it has got to have a lot of crap in it. Sounds like a nice car. Good luck with it.
Car has been tuned, but not sure how much time was spent on the carb. Thanks!
You are welcome and welcome to the Forum. In rereading your post, I see that you said it ran great after the new tank, etc. I overlooked this the first time. This I think continues to point at the carb. If the problem continues, I would rebuild it. if you are handy at all, that is something you can do yourself with the help a book entitled Rochester Carburetors by HPBooks.
Have you replaced the fuel filter? Even if you have there might have been some junk in the lines /new tank. Replace this first. Beyond that look into the carb rebuild. Make sure all the timing specs are set correctly.
There is a small filter that's installed inside the Qjet ... just inside the big nut where the fuel line attaches. Filter available through most parts store for small $.
The Qjet float does NOT come in most kits. Aged Qjet floats are notorious for becoming gas-logged and "fooling" the motor into thinking it needs more gas ... flooding & rough-running results. Float available through most parts store for small $.
Pull the carb ... pull the top half of carb off & spray-clean out both halves ... install new float ... install new filter.
The suggestion to get a rochester manual is a good one.
*another tip ... if you're not real swift w/ small parts or have diminished eyesight etc ... before you pull carb ... get yourself a clean cardboard box and cover bottom w/ a clean white towel ... do most of your carb work/cleaning in or over the box ... that alone can prevent many headaches.
Have you replaced the fuel filter? Even if you have there might have been some junk in the lines /new tank. Replace this first. Beyond that look into the carb rebuild. Make sure all the timing specs are set correctly.
Check to make sure that the choke is opening fully also. It is mechanically operated and controlled by a bi-metal spring that is located on the pass.side of the carb under a metal cover. The spring could be rusty or broken and preventing the choke plate from opening fully.
These are all great suggestions. That is why I love this forum. The fuel filter has been replaced and is clean. I had a feeling it was the carb. Any idea why this happens only when the car is warm?
These are all great suggestions. That is why I love this forum. The fuel filter has been replaced and is clean. I had a feeling it was the carb. Any idea why this happens only when the car is warm?
Have you looked at the idle speed. Perhaps it runs fine when warming up because the choke is on. When the choke is off, the idle is not set high enough to keep it running. Just a thought and something to check out.
Fuel sitting in the carb for that long cant be good either... I'm not saying this is causing the stalling, but I bet your carb got a little gummed up and could use some serivice or at least running a higher dosage of carb cleaner additive in the gas.
These are all great suggestions. That is why I love this forum. The fuel filter has been replaced and is clean. I had a feeling it was the carb. Any idea why this happens only when the car is warm?
If the choke is sticking the air/fuel mixture might be OK when the engine is cold but way too rich for a warm engine. If the choke is opening OK the previous suggestion about adjusting the idle speed would be my next guess.
The prize goes to Jackson. The fuel filter in the carb was clogged. Replaced it, the car started right up and ran strong. This forum rocks!
I'll share it with Gordonm ... he's not so long-winded as me.
Mick ... there's another "filter" ... it's inside gas tank & known as a "sock" ... a (nylon?) net that slips over the fuel pickup tube at right rear of tank. Sock WILL dissolve over time. You're lucky having a 72 'cause it has a large gas cap ... look down in there and to right rear ... you'll see the gasgage float & the pickup tube ... see if there's a fully-intact sock.
If car sat & rust in tank ... that's likely to persist and clog the carb filter again ...'specially if no sock/bad sock. G'Luck!
Thanks Jackson. I replaced the fuel tank and lines in October. Once the carb filter was replaced, the car fired up and ran great. Since this is my first Vette (or classic car), I look at it as a learning experience. Thanks for the help!