M60 Compression Blues

Hello All,

The boat was hard to start after sitting for a month under cover and seemed low on power but I contributed that to have two extra people in the boat. The M60 (Serial A11078) made a metal to metal sound after getting out on the water as the RPM increased and I immediately shut it down. The compression is now at 30PSI on #1 with #2 and #3 at 150PSI. The water pump was working fine at the time.

Is there any last ditch check to make sure it is not sticking rings on #1? If not, is it practical to rebuild? I have the SELCO book but my motor rebuilding experience is limited to Briggs&Stratton and SkiDoo. The ignition wiring is also very brittle and probably cannot be removed without being wrecked. Any idea on a cost estimate?

Thank you for your help,
Scott

Sounds like another motor might be the way to go, used or new. You can figure the cost of some of what would be needed to rebuild but without a tear down you won't know all of it.
Just an added note.... Almost everything I've rebuilt ends up costing more than I figured when I started. I think it has something to do with Murphys Law.
Dan

It will be close on $1000 if you do it yourself and you'll need one piston,but that's new bearings,rings,gaskets and a honing on all cyls,I'm only guessing you'll need a bore out and over size piston and you won't know until you open her up.If you do decide to DIY, which is not as hard as you might think if you have a little patience and take your time try and avoid pulling the block covers unless absolutely necessary.It usually leads to broken bolts and words you don't hear in Church

don't forget to clean those carbs, thats what did it in....jb

Take the plug off, and give a good squirt of oil in the hole, hand rotate the engine a couple of times, then check the compression again. If it goes up, its the rings, if it doesnt its the piston.

Thank you for your suggestions, I did check the compression on the bad cylinder again, 30PSI. Squirted oil in an tried the compression test. 50 PSI. Per your suggestion, I have the motor removed from the boat and will take it to the basement workshop for my winter project. I may as well give it a go before looking for a new motor. I will see if I can replace the rings and take a good look the the cylinder and hone/new rings. Anything else I should make sure to do or not do as long as I am taking the engine apart? This engine does not have a seperate head so I assume I have to split the engine/crank to get at the cylinder.

Correct, ----- a splitting of the engine is required.Most of all you simply MUST determine the cause of the scored cylinder / piston damage.--------If you don't it will happen again.------------------Sometimes people do not have the time to do right the first time,------------but always find the time to do it twice.

"Sometimes people do not have the time to do right the first time,------------but always find the time to do it twice"

I love that line, I'm totally gonna borrow it!

I think you're gonna be horrified at what you find up there in # 1 cylinder. Sorry.

Jeff