87 Johnson GT 150 Motor Please Help

[85stratosman]

I took my motor to the shop and here's the scenario, I have between 6 and 10% leak down on all cylinders except #5 and there is 50% on that one. They will not fix just that cylinder they want to put new pistons in all six. Heres the question, if I buy the piston and rings and all the gaskets is it possible to fix just that one piston to get me back on the water for now until I can afford to drop 3 grand into the motor.

 

[oldrudedude]

Re: 87 Johnson GT 150 Motor Please Help

Where there is a will, anything is usually possible. If it was me, that is certainly what I would try. However, before you commit to the job and buy the parts, you will have to take off the head and/or exhaust cover on that side and access the condition of the walls of the blown cylinder. When you are in there you may find it is just a blown head gasket. Wouldn' that be sweet. good luck

 

[emdsapmgr]

Re: 87 Johnson GT 150 Motor Please Help

You need to understand what caused the failure first. Pull the head on that side. You need to see what is going on in that bad cyl. It will be an easy fix if it is just a blown head gasket. If a ring let go, you are looking at a complete teardown. If that cyl is running lean, you don't want to overhaul it without fixing the problem/cause at the same time. (Do an autopsy on the side of the carb that feeds that bad cyl.) Many times the pistons will clean up enough to be reused. If it threw a ring, you will probably need one new piston (and technically the head, too.) In any event, you really need to go with 6 new ringsets for sure-and hone all 6 cyls. Not unusual for repair shops to recommend higher level overhauls, since they will be providing some warranty on their work. I'd put a new impeller in on any new powerhead overhaul and stats too.

 

[85stratosman]

Re: 87 Johnson GT 150 Motor Please Help

The marine shop told me that on that cylinder it was probably run low of oil to cause that. Now when I pulled the carburators off to clean them the bottom carb that feeds that cylinder was full of old gas and alot of junk. I am just trying to get it back on the water before my bass clubs bass classic and I am on workers comp right now due to an oilfield accident so thats why I am trying to keep from letting the shop due it and cost so much. How would you hone the cylinders?

 

[jonesg]

Re: 87 Johnson GT 150 Motor Please Help

Get the factory manual first, then read it very closely, it does say in fact, you can definately replace one hole.

www.outboardbooks.com

2 stroke engines are very simple to work on, just follow the manual .