2002 Sporster LE 130hp

[Yota]

I was travelling down the cenetr of a large deep lake at around 30mph and the engine lost power and we came off plane, once stopped the engie would not rev past 4000rpm and evenyually shut off. My first thought was that i lost a plug and it actually sounded like that before it dyed. I change the plug and tried again, it started and we went on our way. Just got on plane and it backed off again and stalled. This time it seems like the engine didn't want to turn over very fast, definitly not fast enought to start! took plugs out and checked for compression on both side with thumb over hole while trying to start, seems ok. Almost dark by this time and had to get towed 2 miles to home.
Any thoughts on what could be the problem?
Any help much appreciated

 

[fuchiba]

Check the black ground wires at the left front engine to hull mount...the crimp-on connectors sometime break from vibrations/playing too hard, and the lack of a good ground will cause some real funky problems with the MPEM...this happened to mine once and ended up burning out the MPEM...Luckily it was still in warranty so I didn't have to fork out mega-bucks to fix it:ack: