Sticking Ring Question...'86 BlackMax

[hsdtech]

I bought a boat recently with an '86 Merc XR2 and was told the no.1 piston was out. The first compression check showed 120psi on 5 cylinders and 6psi on no.1. After spraying the cylinder with DeepCreep a few times the compression has come up to 35psi. Today I ran some seafoam threw it and its now up to 45psi. I sprayed it again and its soaking.
Should I just keep spraying the cylinder and run seafoam or should I run it in the water? Should I keep it trailered and just put it under load? Also, if the cylinder, piston, or ring(s) were damaged then compression wouldn't improve would it?

 

[j_martin]

Re: Sticking Ring Question...'86 BlackMax

I bought a boat recently with an '86 Merc XR2 and was told the no.1 piston was out. The first compression check showed 120psi on 5 cylinders and 6psi on no.1. After spraying the cylinder with DeepCreep a few times the compression has come up to 35psi. Today I ran some seafoam threw it and its now up to 45psi. I sprayed it again and its soaking.
Should I just keep spraying the cylinder and run seafoam or should I run it in the water? Should I keep it trailered and just put it under load? Also, if the cylinder, piston, or ring(s) were damaged then compression wouldn't improve would it?

Run it by the nearest real boat mechanic and have him take a peek with a bore-scope and render an opinion. If you bring it in cover off, plug out, it's about a 2 minute deal for him.

You might be able to see if there's massive damage by looking in the spark plug hole with yer bare eye.

hope it helps
John

 

[hsdtech]

Re: Sticking Ring Question...'86 BlackMax

Run it by the nearest real boat mechanic and have him take a peek with a bore-scope and render an opinion. If you bring it in cover off, plug out, it's about a 2 minute deal for him.

You might be able to see if there's massive damage by looking in the spark plug hole with yer bare eye.

hope it helps
John

I've looked in the hole and from what I can see there isn't any damage. Top of piston looks like the rest.

 

[hsdtech]

Re: Sticking Ring Question...'86 BlackMax

After work this evening I checked the compression again and its still at 45psi. I sprayed the cylinder again and then ran the engine for 15 minutes (tank still has seafoam in it). Lots of smoke. I looked in the cylinder with a flashlight, with the piston at the bottom I could see what looks like lots of carbon on the cylinder wall. I brought the piston up and sprayed again. It is soaking again until tomorrow evening. Any other thoughts on my first post?

 

[hsdtech]

Re: Sticking Ring Question...'86 BlackMax

I guess I'll ask one more time to see if I can get any replies. If a cylinder is GAINING compression by decarbing, wouldn't this be a good indication of a stuck ring and not damage?

 

[bryanwess2000]

Re: Sticking Ring Question...'86 BlackMax

You can just pull the head, a head gasket is pretty cheap ~$30-40. My guess
is you've got a broken ring. I wouldn't be trying to run it with 45psi you may
end up damaging the cylinder and piston worse. It would be cheaper to
hone and replace rings than bore and replace piston although that maybe
what your looking at now.
Know that you may break a head bolt when trying to remove them.
P.S. I got 50-60psi on my 90hp after it ate a ring and nearly broke the piston
above the ring land. Just don't get your hopes up thinking it's just a stuck
ring, I'd bet that hole is going to need a rebuild.

 

[hsdtech]

Re: Sticking Ring Question...'86 BlackMax

You can just pull the head, a head gasket is pretty cheap ~$30-40. My guess
is you've got a broken ring. I wouldn't be trying to run it with 45psi you may
end up damaging the cylinder and piston worse. It would be cheaper to
hone and replace rings than bore and replace piston although that maybe
what your looking at now.
Know that you may break a head bolt when trying to remove them.

Thats what I am planning to do. I had the same thought of damaging that cylinder, but was hoping to just get away with decarbing. But I agree with you, its a lot easier to replace rings and hone than to bore. Thanks for the reply.

 

[Dukedog]

Re: Sticking Ring Question...'86 BlackMax

Take it apart and fix it now before it really goes south. These things just don't heal themselves.................

 

[Jack Yates]

Re: Sticking Ring Question...'86 BlackMax

Agreed, fix it before you ruin it. As far as the compression creeping up that is entirely normal when you load a cylinder with oil or another substance. It won't last.

Good luck,

Jack

 

[hsdtech]

Re: Sticking Ring Question...'86 BlackMax

I'm not loading it up when I take the compression reading. I run the motor after I spray the cylinder, then test compression.
Just did the decarb again and its up to 55psi. I'm still on the fence about giving up and start tearing down the motor just yet.
There has to be someone here who has had a similar experience. From 6psi to 55psi, the seafoam seems to be working though very slowly.

 

[j_martin]

Re: Sticking Ring Question...'86 BlackMax

I'm not loading it up when I take the compression reading. I run the motor after I spray the cylinder, then test compression.
Just did the decarb again and its up to 55psi. I'm still on the fence about giving up and start tearing down the motor just yet.
There has to be someone here who has had a similar experience. From 6psi to 55psi, the seafoam seems to be working though very slowly.

If you've had rings stuck that bad that long, odds are real good you have some scuffing on the piston or cylinder wall scoring. I'd pull the head and exhaust cover and take a look if it were mine.

 

[hsdtech]

Re: Sticking Ring Question...'86 BlackMax

If you've had rings stuck that bad that long, odds are real good you have some scuffing on the piston or cylinder wall scoring. I'd pull the head and exhaust cover and take a look if it were mine.

I sprayed some PB Blaster in there, and tomorrow I'll run it on the muffs and check compression again. I might also take it to a launch and run it while on the trailer. I should know by the end of the weekend if I'm going to tear it down.
By the way I did a google search and read that using Blaster and deep creep together in the cylinder really helps stuck/frozen rings.
I might look into either buying or making a leak down tester as well.

 

[huntin dawg]

Re: Sticking Ring Question...'86 BlackMax

I wouldn't run it again until the compression is up where it needs to be. Have patience, let the blaster and sea foam work on it for a week or so. Tilt the motor up and fill the cylinder with blaster and sea foam. Let it sit. I did this with an old johnnyrude and it came right back to life.

HD