Merc 150 Brown Band Electrical problem

[Spritely]

Hi Team,

I had to remove the starter motor from my V6 150 Merc Brown band to fix a slipping clutch pack on the bendix gear. This was no problem, however I stupidly did not connect the Earth lead from the battery to the starter motor. When I attempted to start it i heard a small 'crack sound'. Will I have burnt out a low tension wire somewhere on the outboard or loom?

Once I reconnected the main earth strap to the starter the boat turned over well and ran fine, however the voltage gauge is running under 12 volts and I don't think it's charging now.

Went out for a quick Ski morning yesterday and after about 1 hour of running the tacho started to fail !!

Any suggestions please?
Cheers Spritely

[Mark S]

Appears that you may have blown the rectifier.

Mark S.

[Spritely]

Thanks Mark,

If this is the case, Is this an easy repair?

Would this cause the tacho to start to fail after the motor had been running for an hour or so? Would the tach not appreciate the drop in voltage?

Cheers Spritely

[Mark S]

Tachometer gets its pulse signal from the rectifier, having a blown diode can upset signal. Simple test as per diagram. Being an old brown band I will assume it has this style of rectifier

[Spritely]

Thanks Mark,
Very helpful. Hope to test on the weekend.
Cheers

[Spritely]

Thanks again Mark,

New rectifier solved all problems, had a fantastic day back on the water yesterday

Cheers Spritely