Did a little more troubleshooting after work today... I started by blowing out the idle circuit (mains, too) with my blow gun. I then changed the idle jet in that barrel from a .60 to a .65 and started the engine.
I only let it run for a couple of minutes then shut it down. It wasn’t missing too badly at idle, but after I rev’ed it up a couple of times, it did start to miss. I shut it down and pulled the plug.
I could now smell fuel on the plug and when I wiped it off with a shop towel, the electrode wiped clean – white. The gas cleaned off the slight
oil film.
I am beginning to think this may be an ignition problem. The plug is obviously not firing at all. I don’t think there was enough
oil on the thing to foul it. Before I changed out the idle jets a couple of years ago the plugs would come out black and covered in soot, but would still fire. I guess the cap and new, non platinum plugs are my next step…
MTF
Gun Doc