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Hi. An introduction and a dead Johnson 25

J

J25ELCI

Member
Hi
just signed up to the forum. I have just aquired a 1981 Johnson 25. Model number is my user name as I know I'm gonna need it over the next few weeks/months, so I thought it would good to keep it handy ;)

The motor is currently seized up solid, so I am planning on stripping it down and seeing if it is salvageable. I was told it seized due to lack of use rather than anything sinister, but although it doesn't look like it has been submerged, it is possible it is heat seized, so I am open minded about what I'm gonna find.

no real questions at this time, other than "am I mad for even bothering"? But I will be back when I need advise and hopefully I can document the process and help others too. I'm in the UK so parts are not quite as abundant on the second hand market as they are in the States, so I guess I will end up getting some stuff shipped trans Atlantic.

Actually looking forward to a Winter of tinkering in the garage :D
 
Before you rip it apart you might try getting one of these compression gauges. It allows you to screw one end into the spark plug hole and attach an air hose to the other end. The compressor at 100 psi will allow you to pneumatically push the piston downward with a force of approximately 300 pounds on a 3 inch diameter piston. Squirt in some pb blaster and it will be forced between the stuck piston and the cylinder walls. For this to work, at least one of the pistons has to be in a position where the exhaust ports are not open. This method has sometimes worked for me and at other times it did not. Definitely worth a try.
 
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bobbyc said:
Before you rip it apart you might try getting one of these compression gauges. It allows you to screw one end into the spark plug hole and attach an air hose to the other end. Th P1030041.JPGe compressor at 100 psi will allow you to pneumatically push the piston downward with a force of approximately 300 pounds on a 3 inch diameter piston. Squirt in some pb blaster and it will be forced between the stuck piston and the cylinder walls. For this to work, at least one of the pistons has to be in a position where the exhaust ports are not open. This method has sometimes worked for me and at other times it did not. Definitely worth a try.
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Image should be here now
 
Pull the head and inspect cylinders. If it was seized from overheat check that the aluminum jug casting has not pulled away from cylinder sleeve. If they have the block is non repairable...
 
racerone said:
In simple words-------The aluminum of the block can seperate from the cast in place iron cylinder.
Click to expand...

Right I get you. So the cylinder would effectively be loose inside the block. I guess this will be easy to see once I have the head off.

thanks for the clarification.
 
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