The Stovebolt Site Forums The Shop Area Engine Shop GMC 228 Zenith carburetor- I need some advice

I just bought a Zenith 228 carb from a salvage yard where it was exposed to the elements for many years. I've already ordered a rebuild kit for it and thought I'd get a start on disassembly and cleaning. The problem I have is with a rust and varnish encrusted pump piston firmly wedged in the casting well. I've already mostly destroyed the metal top to the piston trying to remove it. So far, the casting remains undamaged. Right now, it's soaking in some clean gasoline awaiting further progress. I think that I might be able to run a 1/2" tap into the inside of the pump piston to thread a bolt into it to give myself something to grab onto. Or maybe epoxy a bolt inside the piston. So, do I soak this carb in something stronger than gasoline? Apply heat? Attempt to grind, file, or drill from inside the metal remnant of the pump piston? Something else? It seems that the clearance between piston and casting couldn't have been more than a few thousandths of an inch under the best of circumstances so there's not much margin of error.
I'd really like to salvage this project. Any thoughts would be appreciated!

Use an ultrasonic cleaner. Run the ultrasound at maximum, and run the heaters at maybe 165 degrees F.

Jon.

Success! I soaked the bowl in gasoline overnight followed by soaking in lacquer thinner for a few hours more. That removed some, not all, of the old gasoline deposits. I filed two slots into the inner sidewalls of the stuck pump piston with a needle file in order for a flat-bladed screwdriver to have something to grip onto. The real breakthrough came after the application of heat from an electric heat gun on the highest temperature setting applied to the frozen part for about a minute. A few turns of the screwdriver and it was out. What a relief! I hope that the rest of the rebuild is uneventful.

Zenith still makes model 228 carbs.

There are a few missing or damaged parts in my carb not included in a rebuild kit. Mostly check valves and related parts in the accelerating pump system. Does anybody know where I can order individual Zenith replacement parts?

New check valves should have come with the rebuild kit.
Ask Carbking.
Mikes carb shop might have some parts.

Pete

It wasn't the most expensive rebuild kit available. I think I know why now.

I managed to order all the missing Zenith parts from the local distributor. I've read one of carbking's Zenith 228 postings about the potential difficulty of changing out the check valves. I tried to order the special tool for that job from Zenith but it isn't available anymore. So, how do you do it successfully? Thanks!

I haven't done it, but found this link:
http://www.carbkitsource.com/carbs/tech/Zenith/Zenith%20Model%2028%20228.html
"One of the more difficult parts of restoring these carburetors is the removal of the pump discharge check valve (#38), found in the bottom of the accelerator pump bore. This can be removed by screwing a wood screw into the brass check valve and pulling out with a slide hammer. Re-installation should be done with a suitable sized drift so that the valve can be installed square and without damage."