Yamaha I/O no spark

[MEboater]

Anyone know anything about Yamaha I/O's? I have a 1989 5.7L YEMS getting no spark to any cylinders. Worked great last year, the only thing I've done since it was last started is change the fuel pump. Seems like an easy enough problem to troubleshoot, but its got me baffled. Here's the real doozy...although I'm getting no spark when cranking it over, it will sometimes backfire when I turn the key off after trying to start it. Anyone have any ideas? Thanks. Mike

 

[zzzzz]

Re: Yamaha I/O no spark

address your post to Capt. Ken...he's been real helpful with Yammie stern drives8)

 

[MEboater]

Re: Yamaha I/O no spark

Great, thanks. Capt. Ken you out there?!d

 

[Don S]

Re: Yamaha I/O no spark

It's still a 5.7 Chevy, do you have power to the + terminal of the coil with the ignition switch in the run position?
If you have a points ignition, have you checked the points? How old are they? In the marine enviornent points don't last very long. You engine should be tuned up every spring.
The wire from the start solenoid to the coil + terminal may also be bad or the solenoid not working correctly and you aren't getting increased voltage to the coil during cranking.

 

[MEboater]

Re: Yamaha I/O no spark

The YEMS (yamaha engine management system) is unlike anything I've seen. No points, no distributor, 2 ignition coils, several switches and sensors. I think it will take someone with knowledge of this system to troubleshoot it, I sure don't understand it. But thanks for the reply.