Yamaha 90 aeto electrical gremlin

[seadogg]

Evening, I have an odd one that I cannot get to the bottom of...

Couple weeks ago my tilt/trim motor cut out on the way up and the engine started cranking without the key in the ignition switch. After some checking and head scratching i got the trim motor to fucktion normally bypassing the relay and the engine to crank bypassing the solenoid.

I just fitted a few relay and solenoid and neither work without bypassing them again. I tried fitting another ignition switch I have but it still does the same.

Everything works but only when bypassed

Any ideas?
Cheers

 

[boscoe]

What is the engine serial number?

Did the motor start cranking itself at the exact same time the trim motor stopped working?

 

[seadogg]

90 aeto
6H1K L 1000051

I turned the isolator off to check over why the trim stopped. When I turned the isolator back on the engine started to crank

 

[boscoe]

What is this isolator that you speak of? What is its purpose?

 

[boscoe]

90 aeto
6H1K L 1000051

I turned the isolator off to check over why the trim stopped. When I turned the isolator back on the engine started to crank

Approximately 2003 model year is that correct?

 

[boscoe]

No solenoid used in a 2003 90AETO model. A starter relay only.

If the starter motor is being engaged without the key being in the key switch, when a battery switch is turned to the ON position (assumption being the isolator is a battery switch), and not engaging when a battery switch is in the OFF position, then I would guess that the contacts within the starter motor relay are welded together.

 

[seadogg]

I have replaced the starter relay/solenoid with a new OEM one. I wouldn't of expected a new one to have the same symptoms as the one I just replaced

The battery isolator is just an on off switch wired in after battery, before start relay.

I think I have a bad ground somewhere, possible relating to the 703 controls. Im going to investigate that today

 

[seadogg]

No solenoid used in a 2003 90AETO model. A starter relay only.

If the starter motor is being engaged without the key being in the key switch, when a battery switch is turned to the ON position (assumption being the isolator is a battery switch), and not engaging when a battery switch is in the OFF position, then I would guess that the contacts within the starter motor relay are welded together.

Thanks for all your input. Finally got to the bottom of it last night.

Whilst I made sure all 20amp main fuses I was using were tested as good, one of the terminals inside the fuse holder had started to corrode in the rubber sheathing. Only noticed as I was getting good and bad meter readings depending on the angle it was sitting at.

Replaced with new fuse holder and terminals. It's now on the winter list to go through the whole wiring and replace as necessary