2000 Johnson 50 Cylinder Damage. Help!

[FlyingJohnson027]

Hello all, I have recently bought a 2000 Johnson 50 (2 stroke 2 cylinder). It has great compression, reading 120psi on both cylinders upper and lower, and has ran great on a stand. I haven’t seen it on a boat. Upon tearing down the engine more to bring it up to par for the season (just odds and ends). I had inspected the cylinders through the spark plug holes and had discovered the lower cylinder had pitting, almost like little craters in the cylinder wall. I will attach a link that has the photos I was able to take with an endoscope. I’d really like some outside feedback on if the engine will remain reliable in its current condition, or if it would need an overhaul. It may also just be ruined. Let me know what you all think, and thank you so much for your input.

-Matt from Ohio.

https://imgur.com/a/mGXAfdv

 

[racerone]

Motor needs rebuilding.----Cylinder is scored.----Piston is scored

 

[saltchuckmatt]

If you get a chance post both cylinders so others can see the difference.

I would have guessed compression ratios would be different.

 

[FlyingJohnson027]

If you get a chance post both cylinders so others can see the difference.

I would have guessed compression ratios would be different.

I will when I get into it again, those droplet looking parts of the photo are actually pits in the cylinder wall. I’m not even sure if it’ll last a few hours, and I have no idea how it produced 120psi. When I did go into the upper cylinder. It looked clean and perfect as a cylinder should.

 

[Faztbullet]

Those are water droplets from leaking head gasket or water in fuel or oil tank

 

[Crosbyman]

Those are water droplets from leaking head gasket or water in fuel or oil tank

Agree it looks like that........ but OP says they are pits not water ??

I blew up the picture with Powerpoint and perspective is weird to say the least .
seems a bad gasket should drop the PSI's ??? . time to pull the cyl head and peek..inside .and post more pictures.. or wipe it

In any event... with 120psi (?) cost of a rebuild... I would just run it ( not to far from shore...) until till died.

Sad case of buyer beware.

 

[racerone]

They all bark and have a powerful " roar " on a stand.----Means very little to me.

 

[FlyingJohnson027]

Agree it looks like that........ but OP says they are pits not water ??

I blew up the picture with Powerpoint and perspective is weird to say the least .
seems a bad gasket should drop the PSI's ??? . time to pull the cyl head and peek..inside .and post more pictures.. or wipe it

In any event... with 120psi (?) cost of a rebuild... I would just run it ( not to far from shore...) until till died.

Sad case of buyer beware.

After some more investigation this morning, I had the idea come across me to use a can of compressed air and see if I could dry the cylinder up for better viewing of the “pits”. Turns out the “pits” moved around when I hit them with the air. They are indeed water/oil droplets. Now that my blood pressure has settled. I’m going to fog it out with stabil oil, and seal it until season. Thank you all for your generous help and time.

-FlyingJohnson

 

[racerone]

Pull the cylinder head now.----If water got onto the bearings it will soon be a scrap motor.----I say this motor needs to come apart now.

 

[kbait]

I would pull the spark plugs and turn the motor over by hand.. spin flywheel clockwise. If all smooth, assume bearings aren’t damaged. The droplets are obviously water, so you need that dried out of your engine asap. Run motor on muffs or barrel with deep enough water to submerge impeller. Run until warm + 15 minutes. Be positive you have no water in tank/hose before you begin.. it may have had watery fuel on last run that left the droplets.. should dry it up and be ready to go. Good luck!

 

[tphoyt]

Just a thought but maybe it had the head gasket replaced before being sold?
It looks like water was in that cylinder long enough to leave a rust stain on the bottom.
I’m not sure how far you have gotten into this motor but if it were me I would take it all the down for pice of mind before reassembly.
Best

 

[ct1762@gmail.com]

check head to see how warped it is. very common to see bottom cylinder scored. must be really down on power. im doing one now. can finish a whole 2cyl powerhead in a few hours once its back from machine shop.