Blown powerhead

[elcamino12sec]

I have a 1985 dt140, it has always ran perfect.<br />A few weeks ago in the keys the motor began to shake and vibrate, than a little later it began to knock, I backed it down to idle and it made it a few miles before it locked up then I called for seatow, the day before, I changed the plugs and noticed the the bottom plug was milkey. <br />I know the reason that the motor threw a rod was because the bottom cyl got sea water in it, but how? One guy said sometimes the the bottom cyl can get water splashed in it if left in the water overnight when its rough, is this true? any help would be great? Anyone have a rebuildable 140 or 115 power head? I like this motor so much I would rebuild it, but I know it needs hard parts, and a powerhead exchange is only about 1800.00 in Florida.

 

[ARCWINSTON]

Re: Blown powerhead

Hello,<br /> F.W.I.W.i have just been through the same scenario with my 1984 DT140. Cruising along about half throttle, bad rattle, motor stopped instantly as i hooked neutral. I flicked the key and it wouldn't turn over. I suspected it had seized so I let it sit for a while and then turned the key. It started and idled just fine albeit with a rattle. I tried a BIT of throttle and the rattle got REALLY terrible. She seemed to be quite happy to idle so we idled back to the ramp. At home I took out the plugs and # 4 had water in it. A comp. test showed #4 way down so I thought "head gasket". I pulled the head and the gasket was fine but the piston was washed completely clean...no carbon at all. Anyway, to shorten what is stating to become a long story it turned out to be a broken piston. the skirt had failed right through the skirt port. i had lost crankcase comp. and I'm sure it was just sucking water in and blowing it out from the exhaust, hence the clean appearance.I am sure the knocking when I tried a few revs was the start of hydraulicing. Luckily there was no internal damage and she now runs strong again. Parts were not hard to get but were a bit pricey. Hope this helps...W

 

[jim dozier]

Re: Blown powerhead

Interesting. Other places to get water would be from a leaking head gasket or the exhaust cover gasket.

 

[vidar]

Re: Blown powerhead

Hi! mine leaked thru the cranck/driveshaft seal...sucking water thru the leg at plane but not at idle....