Hi!

I have a Yamaha 50 -91 DETOL 2-stroke, and for the past few months it's been
running bad at idle, and sometimes knocks/jumps at medium speeds. At higher
speeds it runs smoothly. At idle it runs OK for a little while, then it
shudders/runs very bad for a few seconds and usually it stops there,
sometimes it won't stop and the regular idle will return for awhle, until it
starts shuddering again. At low/medium speeds it runs fine but sometimes it
sounds like a cylinder would misfire/not fire at all once or twice and then
run fine again.

So far I've tried checking the sparks, changing the sparkplugs, checking the
compression, cleaning the carburators and using a different fuelline + tank,
but nothing has made any difference.

Thank you very much for any ideas or advice you can give me!

Best regards, Tom