1987 88spl

[88splowner]

got a bad piston lil bit of scaring on wall that you can feel.ive talked to a few different marinas some say do all of the cylinders some say do just the one. the others look good and are tight.what would ya do?

 

[emdsapmgr]

Re: 1987 88spl

When you have something repaired at a Marina, they will want to do it to their standards-as they will have to provide you some type of warranty on their work...it's not unusual for them to insist on a more extensive repair. If you do this yourself, you become the mechanic responsible and you can decided what you want done. You are going to have to disassemble the whole powerhead to fix the one hole and probably replace that piston/ringset. Once you get it that far down, I'd at least rering the other three good pistons and hone those cylinders as well.

 

[bob johnson]

Re: 1987 88spl

got a bad piston lil bit of scaring on wall that you can feel.ive talked to a few different marinas some say do all of the cylinders some say do just the one. the others look good and are tight.what would ya do?

what does your version of "do all of the cylinders , or do just one" mean?

BORE?

or just HONE?

I would think if you can catch it with a finger nail..you have to BORE it.

at the very least you should hone and install new rings in all the other cylinders while you are there...

bore means, more labor and a new piston(about $125 )

bore all ..get nice round holes , all new pistons, and rings...

I have heard over and over here and other sites, that is is no big deal to rebore just one cylinder....

I guess the compression and the look of the other cylinders , and how much your budget is......will help you answer

bob

 

[wilde1j]

Re: 1987 88spl

Do means bore. If the compression in the other holes was acceptable, I would consider doing just one hole, with new piston and ring set to the appropriate OS. Let the machine shop tell the OS and use a marine outboard machine shop if you want the best results.

 

[88splowner]

Re: 1987 88spl

thanks for the quick reply and common sense answers.obviously im not a boat mechanic or machinist.i can see a slight bit of scarring on one of the cylinder walls is what i mean,nothing that looks to be in what id say awful shape ill try to post some pics. anyway im thinking hone or at least i hope so lol where is the best place to get parts at a reasonable price?thanks again guys

 

[wilde1j]

Re: 1987 88spl

Honing will just make the ring fit sloppy and the compression low in that hole. It needs boring and the shop will then hone it as well to give the finished cross-hatch. iboats sells parts amd there are online outfits that have complete rebuild sets for ~ 500 to $700, depending on motor. I'm sure you could get one oversize and three std pistons/ring sets in one of those deals.

You need a marine machine shop to tell you what size pistons to get before you buy anything. And don't use an auto machine shop.

 

[bob johnson]

Re: 1987 88spl

thanks for the quick reply and common sense answers.obviously im not a boat mechanic or machinist.i can see a slight bit of scarring on one of the cylinder walls is what i mean,nothing that looks to be in what id say awful shape ill try to post some pics. anyway im thinking hone or at least i hope so lol where is the best place to get parts at a reasonable price?thanks again guys

you never said what the compression numbers were...

I wonder if it is prudent to take a block apart to the point that you can bore a cylinder and then assemble with all the old parts except the one cylinder???( excluding gaskets of course)


bob

 

[wilde1j]

Re: 1987 88spl

Bob, why not with the exception of new rings all around if the bores measure OK in the three undamaged holes?

 

[Faztbullet]

Re: 1987 88spl

Looks of a cylinder mean nothing, I can take a out of round cylinder and run a ball hone thru it and it looks great but its still out of round. All cylinders need to be measured(miked) and if it is more than .004 out it needs boring ,industry and piston standards. Factory manual states .006 from finished hone diameter, so if you hone it to clean it up you increase diameter even more so, bore all 4. I rarely see a engine brought in for rebuilding that is still in spec's that a hone and rings would get by, especially a crossflow(merc & omc) design as there is so much side thrust wear around the port areas.

 

[bob johnson]

Re: 1987 88spl

Bob, why not with the exception of new rings all around if the bores measure OK in the three undamaged holes?

1987!!!

well if you hone the other three nicely and they measure with in spec....sure a new set of rings is all you need..

i am saying...you are there....put a little money into the parts and make it new .

I wouldnt put old worn bearings into a motor i just bored and honed with a new piston!!!


that would suck if a bearing went a month after this tear down...

if i were to do a bore and new piston..Id think id replace all the wear items!!!

most of the money will be in labor i think...

bob

 

[kenmyfam]

Re: 1987 88spl

If the block is off then it makes sense to do them all and start fresh.
Just my 2 cents though

 

[88splowner]

Re: 1987 88spl

the compression was 3 @ 117 1@65 thanks for the responses the top ring broke on the bad piston guy that took it down said hed never seen that. it chewed it up and spit it out i guess there is no indication it has been anywhere else just the one cylinder what got all this started is it wouldnt idle good and it just gets worse and worse lol anyway the boat set for prolly 1 and a half years got it from my neighbor.the boat still ran around 40 43 miles an hour this is my first boat what luck!

 

[bob johnson]

Re: 1987 88spl

dirty carbs can lead to blown cylinders...no fuel or low fuel = no oil

seems after reading threads here for 6 months , that motors blow often after being run after sitting for a while( years).

with out cleaning the carbs..

motors sound like they run fine on 3 of 4 cylinders...

bob