The Stovebolt Site Forums The Shop Area Engine Shop Leather or man made material for accelerator pump

55, 2nd series here....235 engine...

Seems that over the entire 30 years I've owned this engine and its predacessor the accelerator pump has never worked properly. I usually have to shoot the engine with starting fluid to get it started. Pumping the pedal often is not enough. Also on acceleration there is hesitation. The vacuum advance is working.
This past month I bought a kit just because..well it was time to rebuild. The carb had sat a couple of years without running. I've noticed different cup materials are used for the pump. This time I had leather. I see no squirting of gas or other evidence that it actualy is pumping gas and after the rebuild the engine is dry at startup and I get that gasp when going from idle to acceleration.

Just curious if my situation is typical? Is this just the nature of the beast or am I missing something?

Thanks,

Keith

Is this just the nature of the beast or am I missing something?

My Rochester doesn't actually spray gas but it does come out a port inside and it doesn't hesitate at all. I usually use what comes in the kit unless I suspect it has a problem.

The leather is far superior to any of the artifical materials for an accelerator pump.

Having said that, even a leather pump will NOT pump fuel if there is no fuel in the bowl. Modern fuel tends to evaporate from the bowl through the bowl vent (my 390 will evaporate both carbs in less than 2 hours in the Missouri summer!).

To determine if the pump is/is not the problem try the following:

(A) Start the engine. Now you KNOW there is fuel in the bowl.
(B) Stop the engine.
(C) Remove the air cleaner
(D) Open the choke butterfly
(E) Work the throttle from closed to open, you should see a squirt of fuel enter the venturi area. If not, something amiss in the pump circuit (pump, check valve, clogged passage, etc.).

I gave in years ago, and installed an electric pump to fill the carburetor bowls prior to starting.

Jon.