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1988 Yamaha Pro V 150 G black sludge coming out of exhaust housing

1ton

Contributing Member
I heard a little knock when putting it in gear and thought I would pull the gearcase for a quick inspection. Thats where I found the black sludge. If I had ran the engine longer I'm sure it would have came out of the prop. So I checked compression @ WOT and all were between 105-107 psi. However, all the plugs were fouled. Could the knock just been a spark knock because of the fouled plugs? Is the sludge just unburnt fuel being dumped? The engine sat for awhile before I got it. Previous owner tapped into the main wiring harness causing a short that resulted in no power for everything at the control. Fixed that (really needs a new harness) and some burnt jury rigged wires at the starter relay. Thats where I'm at. Water pump is working fine. Should I put in new plugs, the gearcase back on and see if the condition continues? The short knock when putting it in gear and the sludge in my concern. Any ideas what I'm up against? Just needs a tune up? Thanks for any help.
Will
 
Water pump fell apart when lifting it off the drive shaft. Yep, gear oil was a milky green. The water pump was pumping gear oil up into the midsection causing the sludge, right? I looked up into the midsection and that sludge is everywhere. I guess a pressure/vacuum test is warranted. Do you happen to know what psi the pressure/vacuum is pushed/pulled to?
 
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