Oh Oh, this might be bad

[surrender]

Dont know if this is bad but motor is a 1996 88 special. Good compression in this cylinder(121) but was checking for a possible problem in lower starboard hole and found this on piston of upper star. piston. Looks like the leading edge of the piston caught on something and put two little bumps on the edge. No real score marks on cylinder walls and again, compression is good. If pic doesnt come out will try to post better ones later.

 

[OptsyEagle]

Re: Oh Oh, this might be bad

I am no expert but I wouldn't think those bumps would do much. Might create a hot spot that could lead to pre-detonation, but again, others might be able to add some more advice here.

 

[JB]

Re: Oh Oh, this might be bad

Hmmmmm. Looks like it ain't broke to me. If she breaks later, fix her then.

Good luck.

 

[oldrudedude]

Re: Oh Oh, this might be bad

Are there similar marks on the head of that cylinder?

 

[surrender]

Re: Oh Oh, this might be bad

Upon further inspection,looks to be a broken ring on the upper cylinder. pulled the bypass cover and exhaust cover and , yes, ring is damaged. Part of it is missing. So now, can I replace the piston and rings without pulling powerhead? Saw a thread or part of one that went through how this can be done. Cylinder walls look "pretty good".

 

[Daviet]

Re: Oh Oh, this might be bad

You're gonna have to pull the power head to replace the piston and rings.

 

[1946Zephyr]

Re: Oh Oh, this might be bad

Oh boy. Better find out where that piece of the ring went

 

[surrender]

Re: Oh Oh, this might be bad

Thought that was the case(powerhead removal) Guess the piece of the ring is long gone by now and if not I'am sure I'll find it soon....

 

[wilde1j]

Re: Oh Oh, this might be bad

If you're going to do this yourself, get an OEM shop manual and find a good Outboard Machine shop. Such as:

Mar Fab -- talk to Kurt or Dan at 931-738-2815 (Tennessee)

Flagship

Tribble

Blackburn

Roehrs

Riverside

 

[surrender]

Re: Oh Oh, this might be bad

Thanks for all the help guys. Yep, started the minor part of the tear down. Port side looks like new inside, aint that always the case? When I get it to a machine shop I'll find out if the cylinders on the bad side nide major work. If so and I have to oversize I guess that means both sides will have to be done to match, right? Anyway, will be a fun project while I recover from hernia surgery. So far no lifting required, just turning bolts, no broken ones on both sides, yeah! A friend told me I should put it back together and sell it. I probably could but thats just not right, plus when this one is running right(which it did 95 % on the time), its a great motor.

 

[oldrudedude]

Re: Oh Oh, this might be bad

You DON'T have to oversize them all.

 

[surrender]

Re: Oh Oh, this might be bad

Thanks Rudedude. Port side has better compression then starboard so was hoping to only have to do one side. So anyone recommend the best source for parts? I ve seen rebuild kits(for all four holes)for anywhere from 700 on up. Pistons bearings, seals, gaskets ect. Piston and rings alone around 100.

 

[oldrudedude]

Re: Oh Oh, this might be bad

Just do the ones with damage. Best I could find for pice were were $100 per cylinder plus gaskets. If your head has pits in it from the ring fragment beating on it, the head may have to be repaired/replaced also. The smaller fragments of the ring may be imbedded in the head and cause hot spots in the future. Also check the port margins very carefully to ensure no cracks.

 

[surrender]

Re: Oh Oh, this might be bad

Ok, so I 'am thinking of just doing the starboard side. Question, When the powerhead is removed, can I just remove those pistons and leave crank and port side pistons in place? Will all that get in the way or be damaged when any machining is done on the cylinder? Going to call the machine shop this morning and check with them, but like the advice on here. Obviously will have to split the crankcase to remove starboard pistons but do I temporarily put it back together to hold port pistons in place?

 

[194269]

Re: Oh Oh, this might be bad

You need to gut the block so that machine shop can do the work thats needed.

 

[surrender]

Re: Oh Oh, this might be bad

Yup, called them this morning. A couple more bolts and the powerhead is off, cross your fingers on those last bolts. Then into the garage to open it up and remove the four pistons and crank. Guy doing the machining is charging $12 per hole to hone and $40 to oversize that top one if needed, with a complete cleaning of the crankcase. Going to bring heads and exhaust plate/cover and have everything cleaned up and all surfaces done. Looks like the rebuild of one side is going to run about $300-400 for the one side with all new pistons and gaskets.

 

[surrender]

Re: Oh Oh, this might be bad

Ok, all bolts and nuts on studs are off. Powerhead is "loose" but wont come off. Port side rear stud seems to be stuck where it goes through the exhaust adapter. The back starboard one is through the adapter but seems to be free.. Any tips to free it up?

 

[194269]

Re: Oh Oh, this might be bad

Did you get the two nuts above the thermostat and under the exhaust cover? You can barely see them with out a flashlight.

 

[surrender]

Re: Oh Oh, this might be bad

Yes. The port side stud is the one thats seems to be stuck. Got the nut off fine but the powerhead seems to be stuck right there.

 

[surrender]

Re: Oh Oh, this might be bad

New problem thought the rear stud had freed up. When I went to lift the motor the stud was not free. The bolt and part of the case(the back where the exhaust cover bolts on) stayed with the exhuast adapter. Can this be fixed,welded? If not I guess I just trashed a good crankcase.