My Apollo has the 350. It’s my first Buick 350. Had many many sbc but first Buick. It’s all original and stock. It’s the 2 barrel carb. It runs like a dream at idle and when cold. The problem is when it’s warmed up or hot like in traffic it dies and is hard to get started. You have to crank it and pump the gas like a mad man. It acts like it’s out of fuel but it’s not. Then when it goes it misses and barely runs. If it’s cools for a few mins it runs fine but then a few miles down the road it does it all over again. I have heard lots of things. It’s the gas boiling in the carb. It’s the ethanol. It’s the fuel pump. It’s the coil. But rather then throwing money at everything I’m sure someone on here has the problem. Thanks in advance.
You have to diagnose the problem, otherwise, you guess and throw money and parts at the problem. It sounds like vapor lock, but it could be a weak fuel pump, or it could be the engine is running hot enough to boil the gas out of the carburetor. The ethanol in the gasoline will eventually play havoc with the gaskets and accelerator pump in the carburetor. Consider rebuilding with ethanol resistant parts. The 1974 engine could have points or possibly the big cap GM HEI. Which do you have? Consider rigging up a temporary fuel pressure gauge to check fuel pressure. Having that information when it acts up will tell you a lot. I like starting with the simple things first. Have you tuned it up? Put some gauges on it and see what the coolant temperature is. Also get a manifold vacuum reading fully warm in Park.
try it with gas cap loose. if charcoal canister is plugged tank will build vacuum and fuel pump cant pump gas.
I would say tune up, probably plug wires/tune up /gas filter will at least improve things. Weak condenser or coil. When it’s hot , check spark with a screwdriver in a spark plug wire end near a ground. It should easily jump a 1/4 to 1/2 inch gap. What so you don’t get shocked. Do not touch body if you’re holding screwdriver but try to leave it on engine somewhere . If spark is good then it’s fuel. Your sure it’s squirting fuel in carb when it’s acting up? It could be bad/rotten vacuum lines . Maybe choke isn’t pulling off hot. Check plugs for wet or black buildup.
Hand a plug wire to a buddy and ask him to hold it and then turn the key. If it has good spark he will let you know. Jim
