88 Johnson 110 HP Broken rings

waschu2

Recruit
Joined
Jul 15, 2007
Messages
4
My 88 Johnson 110 on my Ranger 320v recently lost compression on the lower right cylinder. I pulled the head and found pieces of piston ring embedded in the piston crown. There is damage to the cylinder wall and the edge of the exhaust ports also. The motor has been used in fresh water only and usually at around 3000 to 3500 rpm. Is this just an age related failure? The water pump was replaced at the beginning of the season and I have a pressure gauge so I know the engine was getting good water pressure. The other cylinders look fine and had compression of 125 psi each. If I replace the power head I am nervous about damaging the new one. Thanks
 

reload

Petty Officer 1st Class
Joined
Jun 29, 2004
Messages
368
Re: 88 Johnson 110 HP Broken rings

Sounds like a piece of carbon broke loose and caught the ring at the exhaust port. How deep are the guoges in the wall? Oh never mind I forgot the exhaust port is damaged. Maybe a new sleeve.
 

Solittle

Fleet Admiral
Joined
Apr 28, 2002
Messages
7,518
Re: 88 Johnson 110 HP Broken rings

Your description of symptoms fit one or more rings failing due to carbon build-up - - usually due to failure to decarbon the engine periodically and/or lugging. Lugging is when the set-up (prop and or engine hight) is out of what is called for thus not allowing the engine to reach recomended max rpm at WOT. You mention usually running at 3000 to 3500 rpm. If this was at WOT you were definately lugging it. Your engine should run around 5500 rpm at WOT.

If you are thinking about rebuilding it, take it apart and bring it to a MARINE machine shop. They will mic the bores and tell you what it would take to get it running. And if you are lucky you will only have to replace one piston.
 

waschu2

Recruit
Joined
Jul 15, 2007
Messages
4
Re: 88 Johnson 110 HP Broken rings

My Ranger is only 16 feet long and with the 110hp at 3000 rpm on plane, my motor is not working very hard. I usually see 25 to 30 MPH which is pretty fast for my lake. The motor is 18 years old with only routine maintenance with years of this kind of use. When I pulled the head I found little carbon on the pistons but, I cannot see the rings. I hope a rebuilt power head will give me a number of years of the same kind of use. I might disable the VRO and add oil to the gas just to eliminate the possible failure of the 18 year old VRO pump. It would be nice to not have to spend a couple of hundred Dollars to replace the VRO pump during the rebuild. Seems to me that a $2K rebuilt power head will get me back on the lake with the least money and time spent. My wife wants a new Boston Whaler but, I plan to retire soon and don't I need the loan. :)
My plan is to remove any carbon in the new power head with Seafoam every 50 to 75 hours or so to prevent and future problems and I will rebuild the carburetors also.
 
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