Bad Fuel Pump??

77SceptreOB · #14 02-02-2010, 01:39 AM

Quote:

the most important adjustment in any carb job(rebuild) is the float height adj. i would almost bet the floats are set too low and the pumps cant constently supply enough fuel to run wide open. therefor the engine will run WOT until the fuel level is lowered, then it slows to an rpm that the pump can keep up with. all of this can be caused by the float too low and not opening the needle early enough and the pump is playing catch-up. what a coincidence the carbs. were rebuilt and this problem shows up. just my .02

Coincidence? Check the floats.
Bones is right on the bulb. I had an emergency buy on a Sat. that fell apart in my hand when replacing. Pulled 4-5" of vacuum @ idle.
Cheers,
GFS

Not sure I follow you guys on the above.

"if the engine consumes 10 gal/hour or 21oz/min and the bowls are full because the float levels are correct". And the fuel pump supplies more than 21oz/min all is well. If the fuel pump provides less than 21 oz /min then the bowl fuel level will drop until the a bowl or bowls dry up and the engine surges due to the engine starving for gas. Then I have to back off the throttle to 3500 rpm at which the Fuel pump can fill the bowls faster than the engine can dry then.

If the above makes sense, then it wouldn't matter what the float level was set at. The fuel supply simply can't keep up with the consumption.....right???

I replaced both fuel pumps BTW.

Am I missing something here?? Please explain.

Thanks,

Jim