2G Accelerator Pump Fix

Needed the wife to come get me in Pete the other night and she couldn't get him started. So the next day I tried myself and immediately noticed gas overflowing the carb. So I pulled the top off and noticed the accelerator plunger cup was torn almost exactly like it was before.


This was quite the delima since the reason I needed the jeep was the Geo's alternator died at the hospital and now we were without transportation with a 25 mile drive to the O'reilly's with the new plunger cup.

Karla grabbed the torn cup and superglued it back together so well you can't see the seams. I set out to find the reason for the damaged cups.

I had never been able to remove the check ball in the accelerator circuit so i started there. All day Saturday using air and every available solvent gave zero success. No manner of snake would fit so yesterday I drilled out the bottom of the carburetor and used a hammer and pin punch to knock out the check ball. It had corroded in over the years and was in there tight. After cleaning everything up real good I sealed up the drill hole with epoxy.


I then installed the correct sized and material (Al) check ball, reassembled the carb and after letting the epoxy cure over night it fired right up and runs like a champ. Drove into town and picked up the replacement accelerator plunger, grabbed some groceries, and towed the Geo home (next weekends project).
On a positive note, the jeep had always lacked a little something off the line. I've never been able to replace that check ball when rebuilding the carb. Now I know why. Someone in the past had installed the check balls backward. A large steel ball is installed into the Venturi assembly, a smaller Al ball goes into the accelerator pump assembly. In the beginning the larger steel ball probably worked ok. Then it lodged in the port and limited the amount of gas that could be pulled into the pump to use when initially accelerating. Lastly it completely sealed up (varnish and debris), flooding out the carb and completely blocking that passage. Repairing that circuit removed all hesitation and boosted low end torque to neck snapping numbers. It is even more of a blast to drive now.

 

Wow! I've had, and have read about many others who've had, a 2G hesitation problem. When I rebuilt the carb I couldn't get that ball out and just skipped it. Your explanation is the first clear direction I've seen on the big/small and steel/AL balls. My hesitation mostly went away but I'm just glad to have this info. I can't remember if the NAPA rebuild kit comes with the balls. If not I'll have to find a source.

Thanks!

 

Akcj, the napa kit comes with the little balls. I got one sitting on my desk.

 

Quadrajetparts.com kit is complete as well.

 

Thanks guys. Great info.

 

Yep. I think I posted this same fix here a couple a years ago. Had to drill hole in bottom of bowl and the reason was the same. Wrong check ball in wrong hole.

 

I was able to remove the check ball in my carb by putting the disassembled bowl in the welding rod oven for a half hour or so. A few taps after that and it came right out. I'm not sure that it would help with removal of the wrong ball in the wrong hole though.

 

Probably not. I put it in a 500* oven for 10 min and whacked it, no go.

 

Great solution!

This is really helpful. I just finished rebuilding my 2G and experienced similar symptoms... Ran amazing for a few minutes and then started flooding, and won't start.

I replaced both check balls during the rebuild but this makes me wonder if I put them in the wrong spots. Also going to look into the torn accelerator pump possibility... Thanks!

 

Another mistake that is made during assembly is when you drop that small ball into the hole, you must make sure the spring seats all the way down into the recess. The edge of the spring covers part of the hole which keeps that small ball from jumping out of the port. I have found that ball resting under (jammed) under the edge of the spring which will render the accel pump useless.

 

Yep. I also had a stuck accel pump ball and tried the oven trick to no avail. Ended up just getting another carb for now and will drill the old one out later. My recent accel pump problem also involved the rubber skirt. I had just rebuilt the carb and it was running fine, when all of the sudden it started to REALLY stumble on acceleration. I pulled the top off and found that the pump skirt had folded up and come part way off the body. I ended up installing the old neoprene skirt on the pump and it runs great now. I've heard the rubber skirts are crap, the neoprene are better and leather is the best. The NAPA kit comes with a rubber skirt, so does anyone know where you can get the neoprene ore leather skirts separately?

 

Thank you sir, good tip! I'll take a look at that spring tomorrow and see if it's seated correctly.

I pulled the carb apart yesterday before work and the accelerator plunger was intact. Also I had actually put both check balls in the correct place, so that wasn't the issue...

Put the carb back on and same symptoms. Immediate flooding, no start.

One thing I did notice is that the long sprung shaft that activates the power valve seemed a little sticky. It moved but feels like it's slightly bent and gets hung up a bit. I wonder if it's too sticky for the vacuum to hold it open so I'm stuck in off-idle mode?

Guys I don't want to hijack this thread. Is this too off-topic? Should I start a new post?

 

When your carb was flooding from the stuck check ball/accelerator pump issue, did it look like this?:



Mine's flooding out those holes in the sides where the bottom butterfly valve's shafts terminate. (wish I knew how to describe that better...)

Thanks!

-Daniel

 

Pretty much. I had gas flowing from everything, as if it was pressurized internally.

 

The accelerator pump will not cause flooding if it is not actuated. Removing the pump completely will not cause flooding. Flooding is caused by needle and seat not sealing and float problems. Trash under needle/seat, needle misaligned and hanging up, float level adjusted too high, float soaked and partly submerged, wrong or distorted gasket between top and float bowl assy. etc.

 

I know what you're saying Walt but something goes on when the passage from the float bowl to accelerator pump seals off. The carb pours gas out of every possible location as though it was pressurized. It's nothing like a float problem. While waiting on each solvent to work I found a lot of the same problems across the interweb in 2g and other Rochesters. Furthermore, there was nothing wrong with my float settings or needle/seat. There was a torn plunger cup and a stuck check ball. After repair of those two items it runs perfectly and no flooding.

 

Well gents, thanks for the tips.

Got the carb issue sorted and I wish I could tell you exactly what was up!

The check ball and spring were in the right place and seated ok. The accelerator pump was intact, and the float settings were correct.

One thing I noticed is that the piston that presses the power valve open was pretty sticky so I sprayed some silicon lube in the hole and worked it smooth. Then I reassembled the carb and it seems good to go now!

 

Okay, so now I've had two carbs with a similar problem -- rubber skirt that came with the rebuild kit pulls away from the pump body, so no squirt. Does anybody know where I can order just a leather pump skirt? Neoprene is a second choice.

 

If the accel pump ball it stuck heat up the bottom of the carb where the ball sits. Get it real hot but don't melt the bowl then tap the bottom of the bowl with something hard and the ball should fall out.