Low compression on 1 Cyilder on mercury 1993 XRi 150

[11b330i]

So yesterday i picked up a XRi 150 with good compression on all but 1 cylinder (has 60) for 300$. Engine looks flawless and all the cylinders except the one have great compression. I took the head off that side and the piston looks all right (the eye test). He said his oil line was dry rotted and cracked thus causing the engine alarm to go off and he shut it off. But then this one cylinder has been low since. Did i get a good buy for 300$? planning on rebuilding it myself and was wondering what im getting myself into.

 

[enginepower]

Did you warm the engine before running a compression test? Maybe that thing has been sitting to long and rings are stuck. Since you know the story on it, I would have removed all the plugs and squirted some 2 cycle oil in each cylinder and ran it for at least 10 minutes before making any judgement to tear it down. If all the other cylinders have good even compression, it would depend on what the cylinder wall looks like for just throwing in a piston and rings and going with it.

 

[11b330i]

also, found this in the engine. Any idea what it is.
http://i.imgur.com/Umaox6U.jpg

 

[Dukedog]

Ta start with 60 lbs ain't gonna come: back. Oiler problem doesn't usually "effect one" cylinder. Where did ya find that? if it was "loose" that's ya oiler problem. That's tha drive pinion for tha oil pump. Really has ta have some help to come outta its hole..........It won't just "fall" out...

 

[11b330i]

he took the engine in when the oil alarm kept going off. I'm assuming the marina took it out, realized the plastic inside was stripped. i am going to remove the entire oil injection system and run it pre mix.

 

[11b330i]

...

 

[11b330i]

The cylinder that gear goes into with the sheared off teeth is the one with only 60 on the compression tester.

 

[Dukedog]

No mater. Its gotta be taken down on and checked, Still havin' some compression in it kinda indicates tha damage is lite. Might or might not "clean up" and get away with new piston in ring. But with any kinda oiler failure tha whole thing SHOULD ta be checked out. Its up to you.......jmo