I have a 2000 Yamaha OX66, 225 HP, EFI 2 stroke with about 325 hrs on
it. Lately if I am running over about 4000 rpm the motor will
occassionally cut out for a second then resume running normally. It's
as if it momentarily gets "unplugged". I can make it happen if I run
head on into another boats wake. I checked the harness going into the
outboard and everything seems fine. The ignition switch seems fine
also. I changed the vapor fuel filter on the outboard with a Yamaha
replacement and also changed the in-line fuel filter/water seperator.
I use premium gasoline and Yamalube and Ring free religiously. I spray
the engine with CRC or WD40 and other than this the outboard runs like
a top. Any ideas?

"Grady White" wrote in message
ups.com...
I have a 2000 Yamaha OX66, 225 HP, EFI 2 stroke with about 325 hrs on
it. Lately if I am running over about 4000 rpm the motor will
occassionally cut out for a second then resume running normally. It's
as if it momentarily gets "unplugged". I can make it happen if I run
head on into another boats wake. I checked the harness going into the
outboard and everything seems fine. The ignition switch seems fine
also. I changed the vapor fuel filter on the outboard with a Yamaha
replacement and also changed the in-line fuel filter/water seperator.
I use premium gasoline and Yamalube and Ring free religiously. I spray
the engine with CRC or WD40 and other than this the outboard runs like
a top. Any ideas?


Could be a failing fuel pump diaphragm. There are 3 of them on that motor.
If they've never been replaced, it could be time to do so.