Engine Performance Loss, Part II

[wildcat]

OK....to sum up:

'81 Mercury Black Max 1500, stock
Had been running 6500 RPM with a 14"-24 pitch chopper.
Suddenly, last week, could only get about 5900 RPM, looked over the engine, did find a bad wire on the Trigger Plate, fixed that, hose tested, all 6 firing happily.

SO, tonight went and lake tested. Same thing, did notice over the wind noise however, that the engine seems to be cutting out at the 58-5900 RPM, about the point when she's really starting to fly. Mostly noticable when I was hitting larger waves/wakes. Almost seems that medium jarring at speed/trim is what is triggering the problem.

Any ideas? Electrical short? Fuel feed? I don't know what to look for next......

Tim

[half fast]

Maybe the "mercury switch" is shorting out.That is a small cylinder of mercury that shorts out the ignition if and when the motor accidently comes up and out of the water,like if ya hit something goin fast.Its blue,just disconnect the wire. half fast

[T-REX]

Check ya fuse holder...I hadone doing the same thing in choppy water and after I about gave up and set it on fire, I changed the holder and fixed the problem...REX

[wildcat]

Rex...what fuse holder that be? Is there one located on the OB itself?

[T-REX]

Yea, should be right above the starter solenoid and have red wires on each end...

[wildcat]

Well, I have looked for the above mentioned fuse & holder, and I cannot find it. Not saying it's not there, but I cannot find it. . .

I DID however locate said mercury switch. I was gonna just disconnect the wire, but my curiosity always wins over in situations like this, so I outright removed it, so I could put it on the meter and see if/how it worked. My thinking, if this is a mercury switch like my thermostat uses, is as I tilt it one way or the other, it would close, causing my meter to make the annoying "beeeeeeeep." Well this thing doesn't do such a thing. It only closed a brief second, then opened up again. I THEN held it about where it would be positioned at speed. . .and I shook it, as to try simulated wave pounding, and my meter beeped happily, much like my motor would 'stall' unhappily. Looking positive I think! Weather permitting tomorrow evening will be lake testing. . .

Tim

[half fast]

No fuse holder on a distrbutor merc.Only adi. ignition. hf