Page updated on 04-25-2018

Accelerator pump repair

09-25-2010, 12:32 AM
Info: 1984 B250, Slant 6, Holley 1945

I've been having an issue with sudden acceleration and have been given advice from multiple people that it is likely the accelerator pump. A quick look down the carburetor shows no fancy stream of fuel when the pedal is floored or when the pump operating rod is manually operated. Looking at manuals and diagrams that I've found, the pump piston cup or spring seem like the most likely parts to have worn out. I'm not seeing these parts for purchase except as part of rebuild kits.

Since I'm having to pull it apart to get at those parts anyway, do I need a full rebuild kit for replacing gaskets and such or do I need to hit up some specialty vendor for the individual parts instead?

Anything else I will end up needing beyond basic tools if I end up doing a rebuild?

09-25-2010, 11:54 AM
Just get a rebuild kit. They have everything you need (including an exploded diagram) and usually cost less than $20.

10-07-2010, 01:13 AM
Holley rebuild kit is on the way, now I get to see if I fix it or totally screw it up.

10-07-2010, 08:57 AM
For a trouble free rebuild, I recommend a 2'x2' clean work area, a can of carb cleaner, and a small plastic bowl to hold small screws and ball bearings. Take your time, make some diagrams or take pictures, as you're disassembling it. Most important of all, clean everything extremely well.

10-10-2010, 03:48 PM
Everything is back in and working better than ever. Idle is smoother, more power on hills, accelerator pump is spraying again, even spun the tires a bit. Not sure how much of that is new parts and how much is just having everything cleaned out.

Looks like somebody rebuilt this in the past and put a spring on the wrong side of a retainer clip on the rod for the accelerator pump. It was just between the clip and end of the rod, not putting any pressure on anything. Moved it to the other side of the clip so now the rod springs back when it is released.

The Holley kit came with a cardboard tray that worked to hold all the little bits. Ended up using part of the box to poke screws through and write the matching part number from the diagram that came with the kit. Overall it was mostly painless (other than the hour+ it took me to get the pump rod grommet into place), just took some time.

Was checking out all the attached hoses and discovered a broken hose leading directly to the EGR amplifier. Taped it back together until I can get a replacement hose. Found a lot of cracks/breaks in hoses where they connect to the vapor canister. Looks like I found my next project.

10-10-2010, 04:20 PM
Nice going, now you're the neighborhood carb rebuild pro! :)

10-10-2010, 04:30 PM
Nice going, now you're the neighborhood carb rebuild pro! :)

It might come to that. There are two other vehicles out here that are having issues with fuel flow that I have been voluntold to diagnose/repair. Both will probably end up with more trips to the forums here. :)

Add your comment to this topic!