90hp wont shut off

[CallalaJohn]

Hello, I have a 1985 Yamaha 90hp 2 stroke. It will start and run no problems, will not turn off. So far I have taken apart 703 control unit, checked for corrosion in joins etc and nothing untoward. I have ohm tested the switch and I get a reading in the off position. I have also checked and cleaned up the 10 pin wiring jacket/housing and all it functioning fine. I have disconnected the white wire from the cdi, started the motor and ground this wire and the motor does not stop. Next I am going to run an independant wire from the switch to the cdi unit and test that. Any suggestions. Thanks.

[99yam40]

did you ground the point on the CDI that the white wire ties into?

[TownsendsFJR1300]

http://www.yamahaoutboardparts.com/f...h23386-p2.html

Post #22 specifically..

[CallalaJohn]

Thanks Boscoe, Towsend and yam99. I conducted checks as described and engine shuts off when earthing wire from white cdi point is grounded. So CDI is good. I ran a wire from the switch to the white cdi point, still will not shut. So now I suspect key switch. Although I get an ohm reading in the off position for that switch. I am stumped. I cannot see any break in the wiring from the switch to the engine. Obvioiusly the connection is not being made. But where, hmmm.

[CallalaJohn]

Just thought I'd post how I fixed the problem. Switch was good. The black ground wire which runs from the switch to the harness was broken somewhere along the line. I tied in a new wire from the black switch wire and cut in before the harness, in the transom area. It was about 4 or so metres of wire. So I looped the black wire in essence. Anyway fixed the problem. There must be a break in the black wire somewhere along the line. Rather than cutting open all that neatly packaged bundle of wires, I looped a new single wire. Summing up, this wasn't any easy fix. Pulling apart the 703 unit, multi metre testing using ohms (resistance), troubleshooting around cdi, it took a lot of mucking around and time. The pictures were very helpful and thanks to others for posting. Hope this helps. Thanks.