Scratches in cylinder wall after hone and piston install

[homelite]

Help! I am rebuilding a 2005 3 cylinder Merc 90. I had the walls honed a machine shop. They appeared to do a fine job. I washed the block 2 times in hot soapy water (after the machine shop washed it when they were done). I installed the 3 pistons with new Sierra rings. I turned it by hand roughly 10 turns after installing the crank, intake, and having it bolted together, etc. I flipped it over to work on the exhaust cover plate, and peaked in the exhaust ports and all 3 walls are scratched. It's enough to feel with a screwdriver.....

Dirt/grit is not an issue. Lubrication is not an issue. Just clearing up that now.

I have rebuild many engines (not a merc) and am an ASE master technician. So..... Is it the Sierra rings? Should I have used Merc rings?

Is this normal for a 2 stroke due to the ports and the rings passing over them the first few times?

If I didn't look in the exhaust port, I would even know. But since I did, what to do about it? What caused it?

I attached a photo in hopes you can see the scratches and give some advise. Some of you guys that rebuild these all the time might have encountered this?? I hope.

Thanks,

 

[gm280]

homelite, at this stage of the game, I would crank it up and run it. I mean if it is serious, it will show up shortly and if it is not anything to worry about, it won't matter. The only think I can even remotely think of is if you installed the rings in the proper direction. Meaning the rings are not installed upside down. If it seriously bothers you, take it apart and check. Otherwise, what else is there to do? It also depends on what type or grit hone finish they did? :noidea:

 

[alldodge]

Help! I am rebuilding a 2005 3 cylinder Merc 90. I had the walls honed a machine shop. They appeared to do a fine job. I washed the block 2 times in hot soapy water (after the machine shop washed it when they were done). I installed the 3 pistons with new Sierra rings. I turned it by hand roughly 10 turns after installing the crank, intake, and having it bolted together, etc. I flipped it over to work on the exhaust cover plate, and peaked in the exhaust ports and all 3 walls are scratched. It's enough to feel with a screwdriver.....

Dirt/grit is not an issue. Lubrication is not an issue. Just clearing up that now.

I have rebuild many engines (not a merc) and am an ASE master technician. So..... Is it the Sierra rings? Should I have used Merc rings?

Is this normal for a 2 stroke due to the ports and the rings passing over them the first few times?

If I didn't look in the exhaust port, I would even know. But since I did, what to do about it? What caused it?

I attached a photo in hopes you can see the scratches and give some advise. Some of you guys that rebuild these all the time might have encountered this?? I hope.

Thanks,

Not an outboard guy, but hand turning 10 times should not do that. If it was mine I would take it apart and find out what happened

 

[Chinewalker]

I agree. If the pistons went in without issue (no binding, etc.) then you should be good to go. If it was able to be turned over by hand, it would NOT have done that much damage.

 

[Faztbullet]

Either rings broken on install,pistons installed upside or ports not chamfered correctly as hone could have knife edged the port.I highly recommend to pull it back apart...

 

[tommarvin]

Please tear it apart, something's wrong. Were here to help, no disrespect the shop did there job correctly the ports need to be chamfered before you install the rings so they don't catch and scratch the walls,or break the rings.
This is going to take some guts, take it back to the machine shop hone cylinders, pay them to chamfer the ports, and put it back together.
Make sure rings are ok, is it the angled side the chamfered side up, oil them before install, use the ring install tool.
Good for you, to ask for help, not many people want or ask for help.