Johnson loses power when hot

[ncyellowfin]

I could really use some expert help here. Engine:
2000 Johnson 90 HP 2 stroke with oi injection plugged and fuel ad oil mixed in tank.

Engine starts fine and runs great at all RPM's for about 3/4 of a mile. Once hot, the engine dies down to 2800 rpm. If I try to go faster, engine just shakes. It will run all day at 2800 rpm. If I shut it off for an hour or more and let it cool, it will shut down again when hot. Engine shakes at 3000 in gear and in neutral.

I have sprayed engine while hot with carb cleaner and no air leaks were deteted.

I think it must be on ignition side. Have installed new plugs but want advice before I drop $300 on power pack and coil.

Thank you in advance.

 

[joereeves]

Does that engine incorporate S.L.O.W. mode?

 

[ncyellowfin]

Does that engine incorporate S.L.O.W. mode?

It does not go into a traditional SLOW mode. It runs great for 2 minutes, then the motor begins to jump and shake. No buzzer.

 

[Boobie]

OMC did have some power packs that would go into SLOW for no reason. Something to think about.

 

[kimcrwbr1]

It could be a faulty stator? Has the engine overheated before? Look under the flywheel for tarlike goo dripping off the stator. Take a timing light out with you and see if it is spark related just lay the light on the deck and see if you get erratic spark once the engine warms up. Can you hold your hand on the head for a slow count to six once the engine fully warms up?