damaged pistsons

F

flatsman

Petty Officer 2nd Class
Joined
Aug 18, 2001
Messages
109
I have a 115hp mariner 1983 model inline six cylinder that has 3 bad pistons --stuck rings--and looks and though a couple of needle bearing have gone through the combustion chamber. Purchased the unit used but it had good compression. Question is where could have the bearing come from. :eek:
 
C

Capt Ken

Commander
Joined
Jul 30, 2002
Messages
2,269
Re: damaged pistsons

If they are little bitty needle bearing, they they've come from the wrist pin in the piston. If they are bigger needle bearing, they they're from the crank end of the rod. Bet they are from the wrist pin and the rings aren't stuck. They're kinda melted into the piston.
 
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graddy

Petty Officer 2nd Class
Joined
Apr 3, 2003
Messages
150
Re: damaged pistsons

There is roller bearings in the rod for the piston.
 
F

flatsman

Petty Officer 2nd Class
Joined
Aug 18, 2001
Messages
109
Re: damaged pistsons

There seems to be a very small needle bearing stuck in the top of one of the pistons. Ok now, what cause this condition? The top of the cylinder is dinged up some , will this be ok or will I have to buff or bush this out ? Every thing seem to be fine except for these pistons and a little bit of aluminum on one cylinder wall. The number 5 cylinder seemed to have heated up somewhat. The motor has a new pump and always has pumped plenty of water. Condition may have been there prior to my purchasing the unit and it finished dieing with me.
 
C

Capt Ken

Commander
Joined
Jul 30, 2002
Messages
2,269
Re: damaged pistsons

What has happened is the cylinders in question has run lean. Lean fuel burn causes the exhaust gasses to get really hot and melt pistons. That's why when you pull the pistons, you'll find the exhaust side of the pistons melted and the intake usually not. To repair this, more than likely you will need to bore the affected cylinders and replace the pistons. The pistons with the needle bearing stuck in them has allowed the bearing to come out the side of the piston and get into the cylinder. You will probably find some bad rods, lots of bad bearings. These inline sixes were famous for doing this.
 
F

flatsman

Petty Officer 2nd Class
Joined
Aug 18, 2001
Messages
109
Re: damaged pistsons

Well, now that don't sound good , am i better off to trash the engine and get a newer one. How often do this engines have this problem. I have a 150hp in the inline six that needs reeds. I am having a to make up my mine to fix or sell the good parts from it as salvage .
 
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