willysmjeeps.com

My M38 recently developed an idle issue. It will idle fine for a couple of minutes, and then begin slowly running rougher until it stalls. I've found that if I disconnect the crossover vent tube to the carb, the problem goes away. The vent tube is clear, as are both of the ends where it connects. I have anther vent tube that I tried in its place, with the same results. This has me stumped as I believe the venting is to prevent a vacuum from developing in the bowl. If the tube and the connections are clear, why does this occur?

Check the tube inside the crossover tube, there is about an inch or more inside the crossover, it connects then bends up an into the crossover... possibly got a bug in there. Use a small piece of flexible wire to snake in and see if it is clear...

I'll try running a pipe cleaner soaker in carb cleaner through there. I was able to blow through it when the tube was connected.

Just thinking of this, try taking the gas cap off. You might be suffering vapor lock...

Tried that already.