My Enticer 250 1-lunger restoration is going pretty well. I put the engine and rebuilt
carb back in on Friday and it started right up. The bad part is that it's still spongy on
acceleration and backfires through the carb both at high revs and during deceleration.
It's likely I've still got carb problems with fuel flow, but there's only 1 real adjustment
on the carb (the air screw). I've either got to tear down and soak the carb (I just cleaned
the passages with carb spray this time since it was running about the same from last
winter) or I've got a problem with points, condenser, timing, etc.

Does anyone have any suggestions on what to check first? My first impression is that
it's likely the carb, but I don't have any experience with old magneto ignitions. This thing
was "well used" when I got it and I'm afraid there may be much more to do before my
son can tear up the yard...

Yamaholic

My first sled was a 1978 Enticer 250. If I remember correctly I had a single wire that came off the coil (don't remember where it went to) that had a splice in it. Whenever it lost contact or arced it would spit and sputter and backfire through the carb. Which kind of sounds like what you are talking about. I would maybe check the wiring make sure you don't have a short somewhere. As far as settings or timing I don't really remember too much about that.......never had to mess with it.

That's a very good point. I was looking at it for a couple of minutes
earlier tonight while putting the blower on my John Deere (SNOW in
Minnesota tonight!!!) I noticed the wiring connections need rework
and there's a crack in the single coil wire. Tomorrow I'm going to get
some new wire and redo several places in the harness. I'll let you
know if that does it!

Yamaholic