Hello,

I have a 1964 Starfire with original 394ci engine and a Rochester 4GC carb. The tag is missing but I believe itīs original.
Is it supposed to have a dashpot/vacuum something?

Iīm experiencing problems with engine power between idle rpm (550) and about 1500rpm. It hesitates even in neutral when stationary and when driving it stalls and hesitates.
When past this 1500rpm it takes off again if you floor it. Donīt know if condition is lean or rich at that point.

Carb has been rebuilt, but reading similar threads Iīm suspecting that one possibility could be the gasket between float bowl and top lock that might be wrong. Need to check that.

Engine is all original.
Ignition side is all new with Pertronix LS1181, cap and rotor, spark plugs and wires and coil. Also mechanical advance was completely stuck so I parted
the distributor which is now loose again. Put everything back with new vacuum advance and set initial timing to 6 degrees.

Made compression test -> all cylinders between 130-150psi. Have not done leak test yet, but engine is breathing heavily.
Planning on doing piston rings during winter time, maybe complete engine rebuild later.

Choke operation has been taken off and the choke plate is stuck in open position.
Accelerator pump seems to be squirting gas when operating throttle linkage. Enough or not, donīt know how to measure it.

Gas tank has been cleaned some years ago. Some gas has been sitting in there ever since. Now Iīve filled new premium fuel about 8gallons.


Any ideas where to look next?

Appreciate your answers,

- Ville

 

Ville, did you rebuild the carburetor? Why do you think the gasket between the float bowl and air horn is faulty? Before you start troubleshooting I suggest you get the choke operational.

 

Hi Jesse and thank you for your reply.

No, actually a friend of mine did the rebuild. There were some problems with the rebuild(ing) kit.'
First the new accelerator pump was plastic/rubber and it leaked so he put the old leather one back.
The new needles(viton ends) and seats leaked also so the old ones were put back.
He checked and adjusted float levels.
He told me there were two almost exactly same kind of gaskets for float bowl-air horn and that he didnīt know which one belonged there.
He said he couldnīt really tell the difference between them but slightly different in some way.

So, does the choke have anything to do with normal operation once the engine is warm?

- Ville

 

No, the choke will just make it easier to start. It is unrelated to the problem your having.

Whenever I've rebuilt a carburetor I always make sure the new gasket matches the old one. If the float bowl/air horn gasket was different and had holes in different locations then that could be related to your problem. As I recall, I've had a few gaskets that were similar instead of an exact match (i.e. holes cut in a different shape) but I've never used a gasket that had extra holes, too few holes or holes in a different location.

That's a bummer the new parts leaked fuel. I suggest soaking the new accelerator pump cup and float needle in a small glass jar of gasoline overnight. When you disassemble the carburetor again go ahead and use them.

BTW, can you get ethanol free gas where you live? If so, then make sure you run it exclusively in your Olds. The E10 gas causes havoc with fuel system seals.