Did a bad CDI can make a weak spark? I mean you have to closed the hood to really see the spark. If you let the hood open at the outside daytime temperature you wont saw the spark at all. You really need the underhood darkness to saw the spark on the 3 cylinders. Brand new plugs, brand new plugs wires, change the stator plate cause the old one was not in the spec! anny ideas?

3 bad coils - of course not. As I said before try it with the key switch unplugged.

no more key switch at all, the guy who own the sled before by-pass it cause it sometimes had the sled to died. After he by-pass it never saw the issue again!

Well that's gotta get you headed in right direction. It is usually some thing simple. Check all your grounds, harness plugs and wires that run under motor plate and near recoil assembly.

Yeah it supposed to be simple, but I can't get my finger on it... I check all wire connector, I repaire all wire that seems to be loose and worn and such. Check the stator plate coils ohm. Everything was good 2 weeks ago. I will check again maybe tomorrow. Ignition coils are in the specs, New plugs and plugs wires... The only thing I suspect for noe is the CDI box. Do you think it can do that?

pop off your flywheel and check for rust contamination. if your flywheel and coils are shorting out, spark will be weak. check your pulser and exciter coils for propper ohm readings. i would bet the pulser coil is weak. your secondary ignition coils are usually pretty stout and don't fail three at a time.

there's no rust contamination at all, I will check the reading if is in the spec, thanks!