94 XP (gotta love the challenge)

[mjm716]

ok guys you have been so helpfull in the past, i just got on this jet ski craze and i bought my 3rd one now. I purchased a 94 XP with problems. according to the guy i bought it from the engine was rebuilt in Michigan in 2007. it ran perfect for all of 2008, but at the end of the season it cut out and started running like crap and backfiring. motor looks great has good compression. i started by removing the carbs and cleaning a ton of crap out of the screens and just generally overhauling them. now they look and seem like they should operate fine. when i try to start it will crank then freeze as if the spark or timing was off and it will do this over and over again, sometimes it will putter for a second. i removed the flywheel and the magneto for testing. any ideas on this will be greatly appreciated. how can i test the magneto and exactly how does it determine the timing. and could the rotary valve possible jump a tooth, these are the only things i can think are wrong. it defenitally has fuel defenitally has spark i just think the timing has to be off. so any ideas for a plan of attack or some kind of flow chart diagnosis would be awesome. thanks again guys.

 

[mjm716]

bump please

 

[SRUSH]

Could have stripped the brass gear on the rotary valve shaft which would throw the rotary timing off and make it not want to crank with the plugs in. Does it crank easier with them out?

 

[mjm716]

just finished pulling the rotary cover off and timing looks dead on, cover is still off should i check the shaft somehow. oh and also the A**HOLE that i am i just checked the electrical box and i have a blown 15amp fuse on the mepm. could this fuse prevent it from starting, remember i got spark even with the fuse blown.