02 90hp 2 stroke runs 2500rpm max

[jwhiiinc]

I have a 2002 Yamaha 2-stroke. It runs fine for 5 minutes, then drops to 2500rpm. Eventually it will run great again, or not. It’s not hot, but I pulled the thermostat anyway. It had sand in the black X, so I cleaned, flushed the engine with water, and reassembled. Ran the same, so I disconnected the sensor (COLD) and found the contacts open. Any advice???

[Colemac53]

Contacts should read OL or open circuit when heated is when it will contact and close the circuit. Your problem could lie with your oil system