Please judge my cylinders!

[Grumpy Bear]

1974 Merc Thunderbolt 50hp. The #3 cylinder had no compression (pic 1) but the rings were stuck and scored when I opened it up. Had to dig them out. Noted a broken reed which probably caused this issue. The other cylinder (pic 2) had great compression but still stuck rings (1 of which I had to dig out of the groove). When I run my fingernails over the visible scores of the cylinders, there is just a slight feel of scratches detected that bump my fingernails. This is a 1974 motor...I don't want to spend a ton of money completely rebuilding it with cylinder sleeves, etc. Just want it to run this motor for a 3-4 years with a handful of uses each year. I'm planning to "hone" these cylinders to de-glaze them with a spring-mounted cylinder hone. Will de-glazing these cylinders be enough to let them last a few seasons?

 

[gm280]

Without being there and taking measurements, It is hard to say. But cylinders that look like that would usually need bored and new pistons. Unless the cylinder is already bored out to max, there is no need for sleeving them. Just have them bored to the next size up, put some new pistons in with new rings and you'll have a great engine again... but that is entirely up to your wants and needs... JMHO!

 

[rookie456]

I just got my 1980 Merc 80hp put back together from a rebuild. My cylinders looked like the pics you are showing. I honed the cylinders and checked them with a bore gauge. They were borderline to acceptable tolerance for taper. I put 4 wiseco pistons and rings on. My compression now is 130, 130, 127, 130, which I think is good. I spent a lot of hours cleaning old gaskets off of mating surfaces. It's a lot of work doing a rebuild. Even though I think my compression is good, I wish I would have had the cylinders bored and used larger Pistons. Then I would feel like the job was done right.
I would buy, or try to borrow a bore gauge and see how far out of round, or how much taper the cylinders have.
Are you using the previous Pistons?

 

[Grumpy Bear]

I just got my 1980 Merc 80hp put back together from a rebuild. My cylinders looked like the pics you are showing. I honed the cylinders and checked them with a bore gauge. They were borderline to acceptable tolerance for taper. I put 4 wiseco pistons and rings on. My compression now is 130, 130, 127, 130, which I think is good. I spent a lot of hours cleaning old gaskets off of mating surfaces. It's a lot of work doing a rebuild. Even though I think my compression is good, I wish I would have had the cylinders bored and used larger Pistons. Then I would feel like the job was done right.
I would buy, or try to borrow a bore gauge and see how far out of round, or how much taper the cylinders have.
Are you using the previous Pistons?

I've replaced 2 pistons (1 definitely, the second for good measure because it had a stuck ring lodged in it and some scoring) and all rings.

 

[henleyhale]

Im with them, rebore and new pistons youll feel better, if not, youll always want to get rid of it, or fear the white smoke again.

 

[Faztbullet]

(1) Mike the cylinders if more than .003 out it needs bored (2) Mike around the intake/exhaust port as this is where inline motors wear (3) Do not use a spring hone as it follow imperfections in cylinder only a rigid hone. (4) Worn cylinders will cause idle and dying when put in gear..It is very rare to find cylinders still within spec on a inline that has had normal use..