Timing

[erik]

I'm in need of help with the timing of my second OC3. I have a functioning mag from my other OC3, I have a good spark but it backfires. The machine even caught fire (had not attached the air filter hose!
Is it possible that I have put the magneto 180degrees wrong?
Spark plugs are dry. Carburettor has all new parts. The starter has a hard time turning the engine despite bad compression and new battery.

Greateful for any help

[Crawler Boy]

On my OC-3 the magneto is timed  for #1
cyl 180 degree from the window on the mag cap instead in the window if i look in my manual
and it runs and work well and itÃ,´s hit the timing mark on the flywheel

[erik]

I changed the timing and got some great bangs out of the exhaust, then the battery died. Will try after new year again.

[Bill Seal]

[Bill Seal]

What kind of forum doesn't let you correct your own posts???
What I was going to say was,  if your starter is weak, one of the brushes may be stuck and not making contact with the commutator.
You could pull all the plugs, stick your thumb on #1, and when it pops off, see which plug is firing. There's no law which says #1 on the cap has to go #1 cylinder (except on old Ford flatheads and Model A's)