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Submitted by Brock O on Wed, 2018-09-26 12:35
Well completed a full rebuild 4 years ago after the rings went.....and again a piston has let go.
Should have the piston and rod out tonight ready for a quick hone and inspection....budget side of it I'm just looking at replacing the one...other cylinders came up 120, 115, 110....Its pre-mix so its always on the rich side, not sure how the exhaust side has blocked up but thinking the heat build-up could have contributed. 1995 Johnson 115HP 2 stroke.
Looking at few weeks for the parts to come...back together for under $300...
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Silver Fox
Posts: 1111
Date Joined: 19/06/14
Hmmm
Something tells me it’s going to be a little more than a quick hone. Maybe a quick resleeve?
My wife understands why I clean my rods n reels in the shower....
Faulkner Family
Posts: 18027
Date Joined: 11/03/08
that doesnt look healthy at
that doesnt look healthy at all. good luck with the rebuild. might be time for an upgrade
RUSS and SANDY. A family that fishes together stays together
ranmar850
Posts: 2702
Date Joined: 12/08/12
That bore looks like it needs more than a hone
? just on the subject of premix, I had some experience long, long ago with racing two stroke motorbikes, and upping the oil in the pre-mix actually had the effect, in general, of actually leaning the mix, due to the higher viscosity of the mix flowing slightly slower through the main jet, IIRC.
Brock O
Posts: 3225
Date Joined: 11/01/08
Rammer...you could be
Rammer...you could be correct, these motors were common for HOT spots in the top cylinder due to an air lock in the water passage, an old Johnson memo gives instructions for a new tell tale location at the top right hand side which i installed during the last build...It does seem to have got to hot...learn mix, too much advanced timing possible.
Yes it needs more than a hone...a sleeve is the only correct fix.
But in this case its going to be a $300 gamble...the two main scores are right at the top and bottom of the stroke so will see how it goes..will lose a little compressioN, MIGHT GOT BANG ON START UP.
I should have just gone through insurance from the start...not sure if they cover these instances.
Will update once its back together.
ranmar850
Posts: 2702
Date Joined: 12/08/12
Credit to you for persevering with the old girl
They are certainly a lot easier and cheaper to work on than the newer four strokes. The only outboard i've actually had fail on me was a 15hp johnson, had a hard life, bought it second hand as my crayboat tender motor. We were coming back up from the mouth of the Ashburton on Minderoo Station, women and kids on board, when it started making bad noises. Nowhere to land but mangroves, so I just kept the throttle open and it made it to where we launched, cut out when I backed off. Pulled the head off and one piston looked like a metal porcupine that had been run over by a lawnmower
Little end had let go, all the needle rollers had been circulating around the charge loop.
Needless to say, it didn't get repaired. Bought a new 15hp yammie at Onslow, lot of trip yet to go.