I've got a 1957 Oldsmobile Super 88. The car has a 1963 Oldsmobile 394 engine in it. I found the car about 2 years ago. It had been sitting for 26 years in the Nevada desert. I ended up getting the car running and it ran on the original fuel pump. I've changed the fuel filter but done nothing else to the pump. Since then I rebuilt the fuel pump and all was good. However, for the last few months I've had problems. Every time I start the car the needle and seat are overwhelmed by the fuel pump. Within a few seconds of running the carb starts over flowing with fuel. It pushes past the gaskets and floods the engine. I've pulled the carb (a 2 barrel) several times and nothing is clogging it inside. The needle and seat look good. I've even done 2 complete rebuilds and changed the needle/seat each time but with no luck.

My question, can the factory OEM fuel pump begin to push too much fuel? I'm getting a fuel pressure gauge to check but wanted to ask the group. Thanks for any advice.

 

Your pump should produce 5-7 psi of fuel. If the viton needle insert dries out, it will cause it not to seal. Often you can "fix" it by starting the engine (or cycling an electric fuel pump if you have one on the car) enough to wet the viton and then wait a few hours before running the engine. In hot weather, it is common for the fuel in the carb bowl to evaporate and let the needle valve dry out.

 

Are you saying this procedure should be done on a car that sits a long time or on every start? I don't have an electric fuel pump on this car just the OEM pump.

 

After a week, no. After four months in hot weather, probably. After a year, certainly.

 

Well then this is probably not my problem. My car gets started up at least once a month. It is also stored inside so it does not sit out in the sun.

 

I had fuel issues with my '68 4-4-2 that turned out to be a repro fuel pump that was pushing over 9 lbs of pressure into the carburetor. On the freeway or open road, the car ran fine. But around town, and during start up and idle, it was blowing black smoke like crazy and pushing raw gas up through the carburetor pump assembly. Switched out to another fuel pump that was pushing the proper pressure and it got rid of the bad effects.

Randy C.
'68 4-4-2 convertible
'69 4-4-2 convertible