60HP 1989 Johnson outboard low compression

[racerone]

Very typical damage.-----Motor needs to come apart for piston / ring work.----Not bad if you can do the work yourself.

 

[Toshi]

Very typical damage.-----Motor needs to come apart for piston / ring work.----Not bad if you can do the work yourself.

Do you mean it needs honing also?

I have never done it…how much would it cost just the do the piston/ring work at boat shop? Less than $1000?
I can do gasket replacement myself.
I live in West Bloomfield, MI.

Thank you.

 

[Toshi]

Do you mean it needs honing also?

I have never done it…how much would it cost just the do the piston/ring work at boat shop? Less than $1000?
I can do gasket replacement myself.
I live in West Bloomfield, MI.

Thank you.

I think I made a stupid question earlier.
I found a guy who can help me to get it honed and replace the rings.

For top cylinder, should I just replace rings? Or Should I get it honed also even though I don’t see any scoring at all?
Can I assume having low compression (100psi) on top cylinder was due to worn ring?
I was wondering why the compression of the top and bottom was the same (100psi) even though the top cylinder has a very smooth wall and bottom cylinder has some scoring.
Thank you.

 

[racerone]

Take the motor apart.-----Do the honing.-----Do the inspection / measuring.-----Determine the cause of the failure.-----Install the latest water pump kit.-----Your " guy " will know all this.-----If he hesitates then find another guy.

 

[Toshi]

Take the motor apart.-----Do the honing.-----Do the inspection / measuring.-----Determine the cause of the failure.-----Install the latest water pump kit.-----Your " guy " will know all this.-----If he hesitates then find another guy.

OK. Thanks.

 

[clemsonfor]

It seems thermostat melted sometime ago.
Top cylinder wall felt really smooth and no scratch or whatsoever.
Middle cylinder wall is the worst among 3. I can see and feel scratches. No wonder this one is having the lowest compression.
Bottom cylinder wall has one scratch but the scratch is shallower than the middle one.

I put pictures of cylinder head and gasket (front and back) if these could help to identify something.

Thank you.

Well just from your description, the scratches are the problem. And with middle being lowest it makes the sense that it was the worst. I could of guessed that one pretty easy.

 

[clemsonfor]

Do you mean it needs honing also?

I have never done it…how much would it cost just the do the piston/ring work at boat shop? Less than $1000?
I can do gasket replacement myself.
I live in West Bloomfield, MI.

Thank you.

The head gasket and honing is very very small part of that job. At a minimum you might be able to take the block down hone the cylinder and re ring it. Maybe new pistons but you won't know till it comes apart. Worse is that you need to bore the cylinders and put in oversized pistons and rings. I doubt a shop would do it for under $1000 as expensive as machine work and labor is these days. But I don't honestly know.

 

[Toshi]

The head gasket and honing is very very small part of that job. At a minimum you might be able to take the block down hone the cylinder and re ring it. Maybe new pistons but you won't know till it comes apart. Worse is that you need to bore the cylinders and put in oversized pistons and rings. I doubt a shop would do it for under $1000 as expensive as machine work and labor is these days. But I don't honestly know.

Thank you. New rings have just arrived as well as gaskets and I will try to replace them to see if compression comes back this Sunday.
By the way, what’s the sign of a bad piston in general? Any scores on pistons are bad and need to be replaced? In my opinion, as long as piston rings are placed properly, minor scratches on a piston shouldn’t matter?

 

[tphoyt]

It depends on what your view of minor is.
Anything that has damaged the ring groves is going to be a problem in my eyes.
For me if I were going this far I would go all the way and replace the piston's and not have to wonder if I did the right thing.
There are rebuild kits out there that will get you everything you need to start fresh.

 

[Toshi]

I am relocating the telltale hose from side of exhaust to the top of the block to prevent overheat. Now I have a question. How do you guys seal the old hole on the exhaust? Any part number exist from OMC?
Thank you.

 

[racerone]

Run to your hardware store-----1/8th pipe plug.

 

[Toshi]

Run to your hardware store-----1/8th pipe plug.

Will do. Thank you!

 

[racerone]

If pistons are scored with grooves in cylinder a rebore with o/s pistons must be done.

 

[Toshi]

If pistons are scored with grooves in cylinder a rebore with o/s pistons must be done.

Thank you for the advice. I am tearing down the engine this week to see.

 

[Toshi]

I am trying to pull off exhaust manifold and and I am wondering if I need to remove the 2 bolts on my 1989 60HP Johnson for it.
Can anybody let me know?
Thank you.

 

[racerone]

???---That would be the intake manifold.-----Powerhead must be removed to do the repair work !

 

[clemsonfor]

I am trying to pull off exhaust manifold and and I am wondering if I need to remove the 2 bolts on my 1989 60HP Johnson for it.
Can anybody let me know?View attachment 366020
Thank you.

That the intake....the carb holes or am I missing something with this picture?

 

[Toshi]

I was going to check reed valves as well…
Excuse me for the poor explanation.
Reed valves look fine to me from outside. I am not going to take it off…

Tomorrow 1 5/16 socket will arrive and I am removing flywheel. Very slow but progressing…

Thank you very much for all the advice!

 

[racerone]

??-----The powerhead must be removed from exhaust housing for this job.

 

[Toshi]

??-----The powerhead must be removed from exhaust housing for this job.

Yes. The powerhead is already off from exhaust housing.