Carb accelerator plunger cause idle problems?

[RebeccaBurg]

Hello again! Am replacing a sticking accelerator pump plunger on a 2-barrel carb on a 1995 350 Mercruiser (Chevy). The plunger doesn't spring back when throttled down. Will this cause the engine to stall when throttled down to idle? (2-barrel Holley)
We cleaned the carb as engine was stalling at idle, 900-1000 rpm on tach, when put in or out of gear after running really great at higher speed. I'm blaming the sticking- open plunger, but wonder if should be looking for other causes...
Am familiar w/ small outboards & this biggie v-8 is a whole different animal.

 

[dubs283]

Re: Carb accelerator plunger cause idle problems?

if the accel pump plunger/umbrella is sticking and your having idle issues i would say its time for a complete carb overhaul

 

[RebeccaBurg]

Re: Carb accelerator plunger cause idle problems?

The carb was cleaned, but didn't have new plunger set. The old one doesn't always spring back after being depressed by throttle. Wondering (hoping) that's why she's stalling when throttling down to idle or if I should keep playing detective.

 

[harleyman1975]

Re: Carb accelerator plunger cause idle problems?

Time to rebuild carb. the accelerator pump diaphragm may be ruptured or very dirty.

 

[RebeccaBurg]

Re: Carb accelerator plunger cause idle problems?

Okay, am ordering a kit.

 

[Walt T]

Re: Carb accelerator plunger cause idle problems?

No the accelerator pump circuit would not cause idle circuit problems. Accelerator pump gas comes out of the nozzles above the venturies, and the idle fuel is just below the opening throttle plates and gas is pulled out by the vacuum that is under the throttle plates. Separate circuits, they have to be.

 

[harleyman1975]

Re: Carb accelerator plunger cause idle problems?

Also look for vacuum leak.