FT9.9ELH sputtering

[deepblue2]

I have a 1987 FT9.9ELH kicker motor with low hours. It starts great and will run all day at low rpms. After it is run at anything above a fast idle for about 5 minutes, it will start to sputter and cycle like youre grounding the spark plugs every second and running on one cylinder. Shut it down for a short while and it will start/run great again at low rpms only. Carb was recently cleaned and the motor runs great at low rpms. I suspect a coil or stator is breaking down when it gets hot. Does anyone know what I need to check this out, such as what type of meter and what the voltage specs are? Any other theories?

Thanks,

Roger P
Saco, ME

[boats.net]

You will need a peak reading volt meter(or meter with DVA adapter) to read ignition output voltage. Test charge coil, pulsor coil and CDI output voltage to see if any are out of specs(specs are in the service manual).

[deepblue2]

Thanks for the reply. Does boats.net sell the service manual? I couldn't locate it on the website.

[boats.net]

You can get manuals at Yamaha's web site, www.yamaha-motor.com