How hard is it to rebuild the accelerator pump?

[renob123]

I think I found the problem with my '85 Brat. The boot around the accelerator pump on the carb is torn, and it's a really good bet that some crud got stuck in there. How hard is it to fix/replace/rebuild this part? Thanks.

 

Jacob

[edrach]

I think I found the problem with my '85 Brat. The boot around the accelerator pump on the carb is torn, and it's a really good bet that some crud got stuck in there. How hard is it to fix/replace/rebuild this part? Thanks.

 

Jacob

Shouldn't be too hard. Boot is replaceable and if the diaphragm is torn, that's replaceable too. There's a place in Fife that reps Webers and they should have the parts for you. Too bad I can't remember the name. Maybe it'll come to me.

[markjw]

Carbs Unlimited is located in Auburn. They can probably come up with anything you will need.

 

I think they use to be in Fife,but moved. Maybe the same place your thinking of,Ed.

 

http://www.carburetion.com/

[GeneralDisorder]

What "problem" do you think is related to the accelerator pump and why?

 

The boot really does nothing other than keeping crap out of the plunger - as you noted. Virtually every single one I've seen has been cracked or torn - didn't make a bit of difference.

 

If you are having off-idle hessitation it's likely worn throttle shafts or a vacuum leak. I have never had an accelerator pump on these cause any kind of trouble.

 

To rebuild the pump, you need to buy a kit and remove the top of the carb. At that point you may as well remove the carb, soak it properly, and rebuild the whole thing. Check you throttle-base as they are often worn out. Rebuilding the pump basically means replacing the plunger with it's rubber pump seal, and the boot. The rest of the pump is a tiny plastic check ball and a spring.

 

GD

[renob123]

What "problem" do you think is related to the accelerator pump and why?

 

The boot really does nothing other than keeping crap out of the plunger - as you noted. Virtually every single one I've seen has been cracked or torn - didn't make a bit of difference.

 

If you are having off-idle hessitation it's likely worn throttle shafts or a vacuum leak. I have never had an accelerator pump on these cause any kind of trouble.

 

To rebuild the pump, you need to buy a kit and remove the top of the carb. At that point you may as well remove the carb, soak it properly, and rebuild the whole thing. Check you throttle-base as they are often worn out. Rebuilding the pump basically means replacing the plunger with it's rubber pump seal, and the boot. The rest of the pump is a tiny plastic check ball and a spring.

 

GD

 

Thanks GD, that's good info. I have a crazy hesitation between 1k rpm and 1300 rpm. When I start driving from a stop, the tach drops to 0, and I almost kill it (sometimes I do) before it'll start moving. From that point it's down on power, but I can get it to accelerate by repeatedly stomping on the gas then letting off. It's not something I can replicate in neutral. Timing and electrical seems fine, and I have new fuel filters. The air intake is fine as well, and I checked most of the vacuum lines I could find.

 

After talking to edrach, I manually moved the throttle, and gas seemed to pour in from the accelerator pump, so I'm starting to wonder if it's something else. It'd be sweet if all I had to do was replace a hose, but I don't really know where to start. I'm not sure which ones are needed and which ones are pollution control things.

 

Any further advice would be appreciated.

 

Thanks.

 

Jacob