Is this Johnson powerhead junk?

Opened the cylinder and found the lower starboard side piston and cover pitted + the cylinder wall is scored.
1979 Johnson 85 Hp

Compression: port side: 138; 138
starboard: 91; (128 the damaged one on picture)

Would it be best to look for a rebuilt powerhead or a good used motor? Should I take it off and try finding a local shop to rebuild it? Will they have to bore all 4 cylinders to keep it balanced or there is a replaceable sleeve inside the cylinder?
The *%$%#ing person I bought it from really got me with this one...

Re: Is this Jonson power head junk?

Re: Is this Jonson power head junk?

I would try and find a good used powerhead. I'll bet there's quite a few years and hp powerheads that wold fit it. Bad thing is, you don't know if your lower unit is good. Don't get the used powerhead/motor unless you can check compression YOURSELF first. Don't feel too bad, we've all been gouged a time or two!:redface:
You might even try to consider it a parts motor and shop for one that is in running condition. I know it hurts but sometimes you gotta count your losses. On the plus side--if all your electricals are good then I'll bet there are plenty of motors on craigslist that aren't running because of electrical problems that you could pick up cheap, especially in that year range.
Good luck,
JBJ

Re: Is this Jonson power head junk?

Re: Is this Jonson power head junk?

jbjennings said:

I would try and find a good used powerhead. I'll bet there's quite a few years and hp powerheads that wold fit it. Bad thing is, you don't know if your lower unit is good. Don't get the used powerhead/motor unless you can check compression YOURSELF first. Don't feel too bad, we've all been gouged a time or two!:redface:
You might even try to consider it a parts motor and shop for one that is in running condition. I know it hurts but sometimes you gotta count your losses. On the plus side--if all your electricals are good then I'll bet there are plenty of motors on craigslist that aren't running because of electrical problems that you could pick up cheap, especially in that year range.
Good luck,
JBJ

Click to expand...

You can bore just one or two or whatever, cylinders. I've done a ton of them.

Re: Is this Johnson power head junk?

Re: Is this Johnson power head junk?

Thanks for the help so far. The motor runs well and no water in the lower unit.
Does anyone knows how interchangeable this particular motor is? For swapping powerheads with other years and Hp.
I should call around tomorrow.

Re: Is this Jonson power head junk?

Re: Is this Jonson power head junk?

Your engine is pretty common. Your 79 85 uses the larger cubic inch 99.6 crossflow block (which was only used on the large hp engines in prior years,)and became the standard bore size for all engines in 1979. It also has the newer base configuration for the exhaust adapter. About any powerhead newer will adapt to your midsection. Having said that, I'm not so sure you should give up on your current engine so fast. When a ring goes, like yours did-it will damage the head and piston, sometimes the liner. You can overbore just one cyl and it will run fine. You could go with one new piston and 4 new ringsets and overhaul what you have. I would look for a new head on the one side.

Re: Is this Johnson powerhead junk?

Yes it looks like the ring was broken and someone did a poor repair. The cylinder has 128 p/sq.in compression which is almost normal but the lining has 2 scratches can be felt by running finger nail over. Last night I was reading two repair manuals and I will repair this motor the way it was suggested by your helpful responses.
This will give me a chance to get involved with outboards a little deeper.
Used to rebuild old VW air cooled motors and some water cooled ones also and have lots of tools. I can still screw up but the motor/boat was fairly cheap and it wouldn't be big loss. I think I will send the starboard side head and block to a rebuilding shop in PA.
Thanks for all the help..

Re: Is this Johnson powerhead junk?

You will need to at least hone each cyl. prior to installing new rings. Try the cyl with the scratches first. You may find they will cleanup with just a light honing. I've seen rebuilt engines run for years with a light scratch on the cyl. wall. The issue is that long-term the exhaust gases will creep down the crack and can carbon up the ring and piston along it. Could take years. A shop owner would probably bore it oversize due to any warranty issues with their work. It's your call.