Johnson 200 V6

I removed the head from the ri

I removed the head from the right side because of very low compression and it appears that the rings have broken and marked up the head but not the cyl wall (smooth). Is there an area below the piston I can't see when it is completely down that could be damaged or would the damage be visible with the piston at that position? I am trying to assess the value of doing a ring job or scraping the engine out for parts.
Any ideas..anyone..?

Classic problem!!! You need to

Classic problem!!! You need to tear this thing down and if it has the original pistons ( rings high up on the piston ) you need 6 new pistons.Wiseco pistons have a much better piston ring set-up.No point putting new rings in an old piston as the grooves are damaged and worn. This is all visible under a microscope or failing that a good magnifying glass.

"David.... It would be a small

"David.... It would be a small miracle if a piston ring failed without causing cylinder wall damage. However, the powerhead must be completely torn down in order to access what is bad, what is good, pertaining to parts replacement.

Many years back, OMC manufactured a piston whereas the piston ring sat very high on the piston, leaving only a few thousands between the top ring groove and the top of the piston. If your engine has this type piston, you would need to replace all of them with the improved lower ring placement piston.

If your engine is a later model (you didn't state the model number or year) and already has the improved pistons, and if cylinder wall damage does exist, the additional cost would be approximately $50.00 to rebore the cylinder and $100.00 for a oversized piston. As I say price is approximate.

Moderl number of engine?"

I do have the old style (1

I do have the old style (1977). I am quite accomplished as a mechanic on auto engines I have not done anything major to an outboard engine so this will be a new experience for me. Will I have to completely separate the block form the rest of the chassis to change the pistons / rings etc.? Sounds like I may need to aquire a manual other than getting the proper torgue amts. etc.....huh?

I have seen a few where the up

I have seen a few where the upper piston ring was completely gone as in " spit out " of the engine with no damage done to the cylinder.Yes you need to remove the block and to split the block.There are no short cuts to this!!

"David..... Yes, with no inten

"David..... Yes, with no intention of insulting your intelligence, obtain a proper service manual specifically for that engine.

The manuals that cover a variety of engines can be quite confusing."