70 ish 75hp chrysler- need powerhead

[Tacoma Tom]

Got this boat. It has 3 cylinders. 2 have 150lbs compression. 1 has 30 where can i get a used powerhead? dont want to buy a brand new one if i can help it.

 

[Frank Acampora]

Re: 70 ish 75hp chrysler- need powerhead

You need to remove the existing powerhead anyway, so why not go the rest of the way: Disassemble it, bore the affected cylinder oversized, and buy a Wiseco piston in the oversize. Boring costs about 60-65 bucks around here may be different where you are at. Piston costs about 125, and associated parts cost about another 50-60 bucks.

By the time you find what you need on say, ebay, then pay shipping, you have done the work yourself in less time and probably for the same price as a used powerhead.

 

[Tacoma Tom]

Re: 70 ish 75hp chrysler- need powerhead

Do you bore just one cylinder or all three?

 

[Frank Acampora]

Re: 70 ish 75hp chrysler- need powerhead

If you are anal retentive and uneven things bother you, you bore all three---LOL

HOWEVER: on these engines the difference in the overbore is so small, the engine doesn't notice it. You can bore only the affected cylinder. The oversized pistons are balanced to factory weight so there is no difference there either.

Guaranteed---the job of removing the powerhead from the midleg will be much more difficult than rebuilding the powerhead itself. So: like I said before: you are doing most of the work already, might as well rebuild--and that way, you know what you have. 150 on the other two cylinders is right on the money for a factory new 75.

And: sometimes due to overheating or oil and carbon build-up, the rings will stick in the grooves and compression will suffer. If the bore has not been scored, you can just replace the piston. As a quick check, take a piece of wire and bend an L in the end. Inset into the plug hole and rotate it around the bore, feeling for deep scratches. Or, remove the head and have a look. However before removing the head, first try a decarbon treatment to see if it frees the rings and compression comes up.