Low speed bog and idle problems Rochester 2g

I have been struggling with a low speed bog right off of idle. I replaced the accel pump and that helped for a bit, as my old one was very brittle and cracked with the slightest touch. However it wasn't long before the bog was back and worse than ever to the point of my jeep not wanting to idle at all. I looked and looked for a vacuum leak, two streams from the accel pump, and figured it was due to something plugging up the idle passages.

I proceeded to order a carb rebuild kit, which I should have done in the first place when replacing the accel pump. This weekend I tore it all down and soaked the carb good, took it all apart and cleaned it real well, soaked it overnight in a can of carb cleaner, and put it all back together.

The new kit came with more gaskets than my carb used, as it must be a universal kit, and when I went to put it back together, it had two thin gaskets and a thick phonelic spacer that went between the carb and the manifold. My old gasket was a thinner one with a metal core. Here is where I found my problems. The old gasket was leaking exhaust into the intake.




Upon closer inspection one of my carb holddown threads in the manifold had corroded enough that the 5/16 bolt was not grabbing. I think that when I replaced my accel pump and put the carb back on the few threads that were holding- gave up the ghost. This excerbated my leak and made the problem worse to the point of no idle and stalling when stopping.


I carefully drilled out the exhaust corroded hole and re tapped to accept a 3/8 bolt, and put it all back together, with the thicker gasket now blocking off the exhaust heating the bottom of the carb.

It now runs unbelievable. Its like a different jeep. No stumble, no bog, will idle at 400 rpm.
Just wanted to share, as I couldn't find any vacuum leak anywhere, didn't expect it to be internal.

Mark

 

I think that the carb hold down bolt has been part of your problem the entire time...

 

I'm pretty sure it has been. I am thinking that a lot of people have this problem and it's hard to chase. I was thinking carb or points.

The exhaust corrodes the hold down bolts to the point of a vacuum leak.

 

Thanks for sharing that with us. All too often there are plenty of reports of problems, but seldom any solution reported.

 

Good fix! Congrats. Good info too

 

did you use that phonelic spacer?

 

I did. I used a gasket/spacer/gasket with coppercoat gasket sealer. I have driven it about 150 miles and it's running great.

 

super!