Date registered: Apr 2008
Mentioned: 1 Post(s)
Quoted: 2 Post(s)
No, Eric, it looks like the part we're after is the little black rubber (almost bell or cup shaped) piece just below and to the right of the top center gasket in the drawing. Or, just above and to the left of the little outside star washer. The pump rubber goes on the plunger which fits in the accelerator pump bore. With fuel in the bore, if you push down on it while looking down the primary carb. bore, you should see a stream of fuel squirt out into the venturi area. If I did it right there should be a picture of a similar one below. It is off a different type carb. but yours is very similar. On the picture you can see where the little rubber piece goes. As I said, if yours is the original, it will be made out of leather.
The function of the accelerator pump is to momentarily provide the additional quantity of fuel needed during acceleration, until the flow delivered from the main metering system increases. This is required whenever the throttle is suddenly opened.
The pump is a piston type pump, operated through the throttle linkage. It is used in stage I only. Located inside the float chamber, it is constantly surrounded by gasoline.
When the pump lever is actuated, the pump piston forces fuel through channels and out through the calibrated injection pipe into the carburetor throat.
Examine pump plunger for damage and sticking. A faulty accelerator pump will cause:
1. Hesitation on acceleration
3. Fuel consumption
Test: Pump lever should have tension‹if not, pump is binding in bore