Other 800 yamaha, wont run in water need help!

[big_goalie]

Resleaved cylinder, New pistons and rings. Compression is 140 in both cylinders. Runs great out of water. Won't start and or stalls in the water. Any ideas?

 

[tipafew]

I'm stumped.......You didn't change anything else when you rebuilt the motor?

 

[superramjet]

Water getting n cylinder somehow, either thru head gasket or exhaust gasket or inner pipe coupler ( if running stick pipe).

 

[Waternut]

Is this a GP800 engine?

 

[big_goalie]

Yes, GP800

 

[john zigler]

i had a seadoo in the shop hear last summer, that did the same thing. good spark, compression, etc.

customer had JUST rebuilt the motor. seemed to run fine on the trailer.

would NOT run in the water, ( under load). i went through the carbs, fuel system etc, completely.

turns out, he had the pistons in backwards. took me for ever to figure out.....