Yamaha 1995 40 hp won't run full throttle

[joehardy]

I have a 1995 40 hp Yamaha that won't run full throttle. It will run for about 3 minutes full throttle, then shut down to a rough idle. It will run fine at 1/2 or 3/4 throttle, but when it is opened up, it runs rough. I have had the casrbs cleaned,and replaced the tank. I have also replaced the thermostat and water pump. At one point, I could turn off the key, and restart it, and it would run fine until full throttle then the same results. Any suggestions? I lean towards heat sensor.

 

[Ray Neudecker]

Re: Yamaha 1995 40 hp won't run full throttle

If the fuel system is working correctly and the motor not overheating, those models did have a high for Yamaha failure rate for the CDI. You need to test for fire when the problem occurs.