[Mechanic]

I have a newly put together M18S that will run smooth without any scary sounds but it will hunt and surge on occasion and then run smooth and will later hunt again. It sometimes starts with a pop which kind of points to a rich fuel condition.

The carb is an adjustable walbro and is pretty clean inside but could probably use a kit, soak and rebuild. Is there any special tricks or methods to rebuilding this particular carb?

For giggles, I turned on the Kv function on my tach and read uneven voltage side to side. The number one side closest to the flywheel and coil read near 10 Kv and the opposite side, number 2 (longest lead) read around 5 Kv. Plugs are new NGK's gapped to .035". Does this point to a bad ignition module and do they vary in output?

If it were yours, what direction would you go in with both issues?

One other question, is the stock carb the only one that can be put on this engine or will a Kohler 26 or 30 carb fit on it?