Crumbling rubber cover on the acceleration pump

I notice the rubber cover of my acceleration pump is cracked and missing a piece. It doesn’t leak. (I re-built my carburetor a few years ago because the AP leaked - it’s disappointing that the replacement has failed so soon.) Does it matter? '87, 2WD, 4-cylinder.

Have you been running ethanol gas thru that 87 carburetor?


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The purpose of the pump is to squirt extra gas when you press on the gas pedal to avoid a stumble or near stall. Depends if you can live with the drveability issue or not but the fix is simple. Seems to me ones I replaced were leather not rubber but either way cheap and easy.

I think you’re talking about the rubber bellows that sits on the outside of the carb, right? That’s not the accel pump diaphragm, that’s just there to keep dirt from finding its way down along the pump shaft. Some carbs don’t have them at all.

Keep driving. The way you use your truck it may be next decade before it’s a problem.


Yes, for at least 20 years.

I only know of it as part of a carburetor rebuild kit, which is expensive for such a thing.


What I thought. If it were really the diaphragm I wouldn’t even ask.