1998 Evinrude 115hp SPL - Just ate a ring, what next?

[Mutt606]

On the last 20 minutes of our vacation this summer our 1998 Evinrude 115 SPL ate a piston ring (my best guess). At mid throttle I lost a cylinder. I pulled the plug on the water and the end was smashed closed. I spread the plug and got it back to the dock. At home today, I checked compression:
Port Upper = 125 psi
Port Lower = 125 psi
Starboard Upper = 60 psi
Starboard Lower = 110 psi

I pulled the head and my heart sank. I included the photos.

I have the shop manual. What is my next step? I don't have the money or a new motor and don't want to spend $2500+ on a rebuilt powerhead.

Can I just replace the piston and rings and go about my business or is the motor scrap metal?
There is a score in the cylinder wall that will catch my fingernail, visible in the picture, about 1/4" long near the upper port (it corresponds to the largest chuck taken out of the piston).
Do I need to re-bore the cylinder oversize (I think they are currently stock as I measured 3.500")? If so where can I get that done?
Do I replace just the rings on the other 3 cylinders while I am inside?

 

[Scott Danforth]

your local engine machine shop can bore and hone the case

 

[interalian]

If you're handy, try the job yourself. I did and saved a metric tonne of $$.

Have a good look at the other pistons to be sure the ring lands aren't worn and aren't scuffed up. Have a shop measure the bores and see if there's any taper or out of round. You might get away with one piston and a hone job. That plus a gasket set and your time will have you back on the water for cheap.

 

[racerone]

Some will argue -----I see that damage all the time.----Every one of those motors will suffer from the same fate !!!----Putting new rings into worn piston ring grooves is a wasted effort as well.

 

[Wkd179]

If you are going to repair it?? all new pistons and rebore over size...If you don't replace all piston be prepared for the same thing to happen in the very near future. If you don't rebore motor will be noisy

 

[Mutt606]

You all are making me think that since I plan on keeping the motor I should do 4 pistons and rigs. I haven't been able to call around for machine shops yet, what would a reasonable price be to re-bore all 4 cylinders 0.020 over? I'm starting to get excited about doing this myself.

 

[interalian]

I spent around C$1400 to do mine two years ago. If you're going ahead, have the machine shop tell you how much it will need to be bored to clean it up. I went 30 as I had a pretty big ring strike burr in one port. I had a bit of fun finding a shop to bore it as none of the local ones could bore a blind hole - ended up going to a motorcycle shop.

 

[Mutt606]

Well, I took everyone's advice. I have never attempted something of this magnitude before, but I dove right in the deep end. It took me 5 8-hour days from start to finish. Started it up today and it started first crank without advancing the throttle (something it had never done since I owned it). Incase anyone is wondering, I thought it was very easy job, almost relaxing. I would love to do another for fun or money. I used factory manual, and it was very easy to follow. I used Joe Reeves timing method to set (didn't have to adjust) the timing.

I went with boring all four holes 0.020" over. Local shops couldn't do the blind hole, but found a shop 1.25 hours away that did it for me. I didn't do any bearings, they appeared to be perfect.

Cost

• $330 - machining
• $200 - four pistons and rings
• $100 - gasket kit
• $30 - rod cap bolts
• $75 - various glues, adhesives, etc
• $14 - impellor
• $15 - fuel pump kit
• $20 - thermostat kit
• $50 - various tools I needed along the way

Just an idea what the next person might expect.

 

[interalian]

Nice work. Sure is a great feeling when your efforts give immediate reward. Mine started on the first try too.

 

[Faztbullet]

Make sure you break it in properly