I have a 140hp Yamaha 1985 model. I have an intermittent high pitched noise coming from the forward lever control unit. Motor appears to run ok even with the noise although I throttled right back to avoid possible damage. Turned the motor off and then back on and the noise continued. Then I turned the ignition key slightly anti clockwise and the noise stopped...but I lost power to the instruments (trim & Tilt, oil lights etc). When it is there the noise continues whether in neutral or in gear. I have had trouble where the motor does not stop when the key is turned off (only happened twice in twelve month so very intermittent and the ignition in the forward control has been replaced 2 yrs ago)they could be related?
could be a bad ground. if its just a 703 type control box(standard yamaha control) split the halves and check for corrosion. also pull your main harness plug, located under the engine cowl on the stbd side. and check for corrosion there also.
Finally got afew hours to have a look. Everything was in pristine condition, no sign of corrosion anywhere, except a tiny bit on the locking nut on the choke switch. Pulled the connectors apart on all the leads and they were like new. Same with the main harness plug. I'll wait and see if the problem re-occurs next time I'm out, I've run the motor with the muffs on here and it hasn't happened again
140 Yamaha noise in forward control unit
on the stbd side. and check for corrosion there also.
Linear Mode
