Accelerator pump kit

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NWAspider

Accelerator pump kit

Post by NWAspider »

I looked around before posting and while I found a few about accelerator pumps, I didn't see any instructions. I'm leaking from my accelerator pump (at least after looking at diagrams, I'm fairly certain), and having a problem where my rpms drop suddenly during idle when the car is warm. I'm hoping an accelerator pump rebuild kit solves this. I got my parts in yesterday, and I'm not really sure what to do next. Judging by some of the pictures I've found the pump seams to be very similar to a small motorcycle carb. Diaphragm with a spring basically. This weekend I'm going to pull the accelerator pump off and see if I can do this. Is there a good set of instructions to follow, or is it going to be fairly straight forward? 1-pull accelerator pump off. 2- open it up. 3- carb cleaner. 4. replace diaphragm and gasket. 5- put back together 6-bolt back on. This is pretty much how it's playing out in my head. I'm I way off base?

thanks again for all your help. I don't think I could keep it going without this place.
NWAspider

Re: Accelerator pump kit

Post by NWAspider »

If this helps I found a picture of a carb online.
Image
TronDD
Posts: 68
Joined: Tue May 17, 2011 4:29 pm
Your car is a: 1979 Fiat 2000
Location: Massachusetts

Re: Accelerator pump kit

Post by TronDD »

I wouldn't think this will fix your idle rpm problem.

The accelerator pump only comes into use when you push your foot down on the gas pedal.

If the accelerator pump is leaking INTO the carb throat and into the motor, it could be an inconsistent leak that is changing your idle RPM. Without a diagram of the Weber carb in front of me, I am not sure that could actually happen, though. You could test this be turning your idle screw all the way closed while it's idling at it's faster speed. If it can idle with the screw all the way in, it's getting fuel from somewhere else.

Tim.
1979 Fiat 2000
1986 Trabant
1969 Chevelle
2003 Jetta TDI (Daily driver)
NWAspider

Re: Accelerator pump kit

Post by NWAspider »

TronDD wrote:I wouldn't think this will fix your idle rpm problem.

The accelerator pump only comes into use when you push your foot down on the gas pedal.

If the accelerator pump is leaking INTO the carb throat and into the motor, it could be an inconsistent leak that is changing your idle RPM. Without a diagram of the Weber carb in front of me, I am not sure that could actually happen, though. You could test this be turning your idle screw all the way closed while it's idling at it's faster speed. If it can idle with the screw all the way in, it's getting fuel from somewhere else.

Tim.
Thank you, I heard another problem could be a vacuum leak. The accelerator pump is still getting fixed asap, as I am leaking fuel when I accelerate. Thank you for the advice on my idle issue.
majicwrench

Re: Accelerator pump kit

Post by majicwrench »

That pump diaphram is super easy, just the 4 screws, make sure when you take it off you don't lose the spring. Pay attention to diaphram and spring and put in same way. Then new diaphram, don't overtighten screws.
Keith
So Cal Mark

Re: Accelerator pump kit

Post by So Cal Mark »

the pump cover may be warped, causing the leak rather than a failed diaphragm
NWAspider

Re: Accelerator pump kit

Post by NWAspider »

So Cal Mark wrote:the pump cover may be warped, causing the leak rather than a failed diaphragm
I hope it's not that, but with my luck I get the feeling it will be. Do you know where online I can get a new one? Searching online is just turning up diaphragm kits.
majicwrench

Re: Accelerator pump kit

Post by majicwrench »

Don't assume it is warped, take it off and check it. In my experience is more likely diaphram. IF cover is warped, just put some sandpaper on a level surface and rub cover over it till flat. Diaphram will take up quite a bit of un-evenness (is that a word?) in the cover anyway.
This a simple job, don't make it more than it is. Don't overtighten screws.
Keith
So Cal Mark

Re: Accelerator pump kit

Post by So Cal Mark »

the problem with sanding the cover is that it takes off the ridge that seals the diaphragm. I'm not guaranteeing it's warped, but I'd look at it closely. It's a common problem on these carbs
NWAspider

Re: Accelerator pump kit

Post by NWAspider »

As always thanks for the advice, got the new diaphragm in, pulled the throttle and saw no leaks, unfortunately on the first drive to work I broke my idler arm. I love my fiat.
narfire
Posts: 3959
Joined: Sat Dec 27, 2008 2:14 am
Your car is a: 1980 124 spider
Location: Naramata B.C.

Re: Accelerator pump kit

Post by narfire »

NWAspider wrote:unfortunately on the first drive to work I broke my idler arm. I love my fiat.
Now remember... F I A T fixing it as thearapy
80 FI spider
72 work in progress
2017 Golf R ( APR Stg. 1)
2018 F350 crew long box
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