Wombat carb rebuild

[matt glascock]

I'm in the process of rebuilding a stock carburator on a model 94 wombat (Build 7/72, F# C-04685, E# H-17308). This involved complete disassembly, cleaning and replacement of pilot jet (#25),banjo bolt and gasket, stock (140) main jet, float needle and seat, gaskets, plunger-type starting enrichener, and needle jet o-ring. I've noticed that the needle jet o-ring appears slightly larger than the one it replaced. Now, I'm having trouble fitting the float bowl to the top assembly. They line up ok but there is resistance getting the mating surfaces opposed. Is this due to the slightly larger o-ring? Before I deploy the two most frequently used arrows from my quiver (brute force and ignorance) and apply serious (198# weakling) grawnch to the assembly, has anyone experienced this on a rebuild? As always, thanks to all for guidance.

[Dale]

Matt,
Try testing just the o-ring into the float bowl opening where it is to fit. If that looks okay, remove the nozzle and then test the fitment of the o-ring and nozzle down into the float bowl without the upper carburetor blocking your view. I always coat the o-ring with a little grease for installation.
Dale

[matt glascock]

Cool. Good call, Dale. Thank you!!

Best,

Matt

[Bullfrog]

I have experienced tight fit of new O-rings into the little bowl at the bottom of the float bowl. It would be good to do the test Dale suggested with the needle jet (main nozzle) and O-ring assembly removed from the carb - you'll be able to see and feel the fit at the same time then. Probably it will be OK. Then you can do the carb assembly with confidence after the test fit proves things will go together OK. But do "push"/lightly twist the float bowl to very near full seating before installing the 4 float bowl screws - and use the grease (or some of your pre-mix oil) as Dale suggested. I just don't like the concept of loose fit up, then using the screws to force the float bowl into place - too much chance of warping the float bowl screw "eyes".
Ed

[Bill2001]

And remember that o-ring is critical-- _any_ leakage will alter the fuel flow at the main jet.

[matt glascock]

Excellent! Thanks, fellas! I'll make a dry...er...greased run with the o-ring/needle jet assembled but removed from the top of the carb. I didn't want to use screw-power alone to complete the fitment. Its good to know the role of that o-ring plays in the matter of flow through the carb. I'll get to it after work tonight and report. As always, many thanks!!

Best,

MAtt

[Bill2001]

Typically I use Vaseline for carb assembly. Pure petro jelly, no additives and dissolves instantly in gas. GIGL

[matt glascock]

All good! Runs like a top!! Thanks to all.

Best,

Matt