Heat Related Failure--Update

[fastjeff]

1989s Merc triple. Runs fine for, say, 1/2 hour at speed, then slowly dies as the motor is pulled back at idle.

Did some more experimentation yesterday after it died again: My DVA meter said the blue wire off the stator (low speed coil) was putting out 220 volts at cranking speed. (Excellent.) Like a dope--actually, I panicked 'cause the boat was drifting out into the river!--I didn't check voltage on the coils.

After paddling (again!) to a nearby pole (15 minutes or so) I put the DVA on the coils and cranked her over--135 volts on all three. The insolent beast then started up on me as I was doing this, which proved nothing! It died again a few minutes later, after which it fired up a few minutes, and it also started up after I put the boat back on the trailer (with good DVA readings everywhere).

Conclusion? I haven't one! If I had checked the coils after it died the first time I might have one, but...

Frustrated Jeff

PS: I have a new switch box that I'm gonna try next. Of course, if the motor doesn't screw up again (and I might not) the problem might remain. Oh, for breaker points and condensers again!

 

[galamb]

Is there a Mercury switch on this one Jeff?

If the stator is showing good, at least at the low speed windings, something might be sending that power to ground before it gets to the coils...

 

[fastjeff]

I, ah, found the damn problem. Cost me a fortune in replacement parts (along with weeks of frustration).

The safety shut off lanyard switch was shorting out inside. The little b*st*rd didn't do it all the time, just when it was most inconvenient--like when it was a loooong paddle back to the dock. Stumbled onto it by pure luck.

Jeff

 

[faztbullet]

Runs fine for, say, 1/2 hour at speed, then slowly dies as the motor is pulled back at idle.

That wont cause the problem you stated as if it shorts ignition goes dead ..wont cause it to slowly die as stated.It would be boom like key was cut off . More likely one of the parts you changed fixed it...

 

[fastjeff]

Not so sure (though I'll soon find out--ordered a new switch).

I know what you're saying, but it wasn't a dead short, just one of those kinda dead shorts that come and go--the kind that drive people nuts.

Jeff