Is this scoring really bad?

[tboydva]

Today, my '95 Evinrude 60HP died after running on a plane. Couldn't for the life of me figure out why on the water. Got home and did a compression test. 105; 75; 110. Was worried, so I pulled the head. It looks like the top two cylinders are "dry." The bottom cylinder was oily and I could see the x-hatch hone pattern still on the cylinder wall. Now that I think back, the last few times I took her out, she seemed to plane a bit slow. My last carb rebuild was not last winter, but winter 2010. Inspecting the cylinder walls more closely, it looks the top and middle cylinders have a small amount of scoring (pictures attached). The bottom cylinder (picture also - the last one) looks good.

So, my question is, do I assume the top two carbs are gummed up, rebuild the carbs, seafoam the cylinders, and run/check compression and hope for the best - or does this scoring look significant enough to consider a rebuild? I've only rebuilt two outboards, so I'm not super confident in getting into a job of that proportion if I can bring this back to life. I put about 50 hours on her a year. Any advise from the gurus???

Thanks.

 

[1946Zephyr]

Re: Is this scoring really bad?

Yikes. Those cylinders look scary. I would recemend a rebuild, myself. You may be able to clean those cylinders up and get the galling off, but the pistons are likely toast. You may be able to get good quality used pistons, versus buying new, if you want to save a few bucks. That motor is pretty late and should have a pretty good used parts availability. It does sound like the top cylinders aren't getting enough fuel, if they got chewed up like that.

 

[metriccrescentwrench]

Re: Is this scoring really bad?

It's hard to tell for sure, but from the photos it looks like there's something deposited on the walls of the middle cylinder in a few places (aluminum ?), which makes sense considering the compression numbers. In my opinion, no, throwing SeaFoam at the problem and hoping for the best isn't going to get you anywhere.

 

[tboydva]

Re: Is this scoring really bad?

Not what I wanted to hear (but what I expected)... I sprayed a little deep creep in there and wiped out the cylinders. The middle one has some scoring - but by feel, it's seems worse in the pictures. I'd say maybe a half millimeter in one or two places. Not sure about any "deposits." I think it could be an artifact of the photography (hard to take a picture of shiny metal). 1946 - you say the pistons could be shot? Do you mean the rings? I guess I'd have to pull the crank and pistons out and see how they look? I presume I could get the cylinder honed and get oversize pistons if I need to? Perhaps it's time to consider a newer outboard (although trying to pull the wiring harness through makes me want to avoid that at all costs). Looks like no matter what, I've got to pull the head off at this point? I guess fishing is done for this season....

Thanks for the rapid responses!

Tom

 

[boobie]

Re: Is this scoring really bad?

What 1946 meant was if the cyl's look that bad the piston skirts are probadly scuffed too. With that you will never get it to idle properly. Time for a tear down or different mtr.

 

[1946Zephyr]

Re: Is this scoring really bad?

Thanks boobie. That's exactly what I meant. Yes, my friend. You will need to replace the pistons, because they're most likely scored to beat hell and probably look worse than the cylinder walls. The cylinder walls can be cleaned up and honed and most likely be fine, unless there is scoring in the cylinder. That usually happens if a ring breaks or a chunk of the piston come lose, so I think you escaped cylinder damage. You just need to clean up the cylinders and have them miced out. Your rings might actually be okay to re-use too. Just your pistons are shot.

Don't be too discouraged. A good mechanic can have you back on the water by mid August.

 

[tboydva]

Re: Is this scoring really bad?

Thank you gentlemen. I had a mechanic in my area I really liked, but his last job wasn't so hot. For starters, perhaps I'll pull the head and prep it for rebuild. This motor looks brand new (last time I pulled the head, I repainted). Not sure if anyone has a recommendation in the Washington, DC area - but I'd like to hedge my bets onto a really good mechanic.

This leads to the question - how does one know this might be happening? As I said, when I think back, I can now recall that the last time or two out, the hole shot seemed weaker (I have a 16ft aluminum boat that this motor usually shoots out of the water). Up on a plane, it ran very smoothly though. I think the top cylinder's carb went dry yesterday and that's what killed the engine (it stalled out and wouldn't start). I use dry-gas in every tank to try and alleviate the hygroscopic nature of the ethanol additive. Perhaps it's worth rebuilding the carbs every season? In my old motor ('83 60HP which I still have and still runs), I only rebuilt the carbs every three or four seasons when it started running a little rougher. I'm thinking perhaps I will swap out motors for now and get the '95 fixed right...

Thanks again.

 

[Faztbullet]

Re: Is this scoring really bad?

I use dry-gas in every tank to try and alleviate the hygroscopic nature of the ethanol additive.

Dry gas additives are mainly isopropyl alcohol and oil will not mix with it. It is possible that you got a slug of pure alcohol that settled tobotom of tank and it wash the cylinder wallss clean..either way it needs a overhaul...