Seized motor piston rings

[billy-j]

Hello. Working on a 1956 Evinrude 15 HP. motor. Got it from the scrap yard. Engine was seized I removed head and cylinders had water in them and cylinders were slightly rusted. I cleaned up the cylinders with sand paper and took a wood block and with a hammer lightly went back and forth on the 2 pistons and it did not take much and they were moving pretty well. It turns over about 85% of a revolution very easily. I did not want to force it to turn a full revolution because water was also in the crankcase and I am sure there is some rust on lower part of cylinder internally. I think the engine was low hours from overall condition and visible original cross hatch marks. My question is if cylinders are in good condition could I just give it a light hone and if I remove original piston rings and kept them in order of removal from pistons also give them a clean up and reinstall on original pistons and expect a good result? Do the rings rotate around in ring grooves as engine runs? Let me know. Bill,

[Bob Wight]

If there was water in the cylinders to the extent the pistons were stuck (even if now have it partially freed up) you really need to split the crankcase and assess what damage has been done to the crankshaft and bearings and how badly the lower portions of the cylinder are rusted. I’ve had a few motors in the same rusted/stuck condition when I got them. One of them was saved with new crank/rod bearings and a cylinder hone job. Another one needed a replacement block and one new piston and rings. And another one was total junk and I had to find a good used powerhead. Your piston rings should be free in their grooves but they do not rotate in the grooves – there is a locating pin in the groove and the end of the rings straddle the pin – see pic. I’d recommend you open the crankcase to determine extent of the water issue and next steps needed.

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1955 Johnson QD-16
1957 Evinrude Fastwin 18
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."

[frankr]

Agreed, open it up.

[fleetwin]

Yeah, if it is tough to turn over, chances are there are internal issues… You can try to loosen it up, but you may cause more damage by trying to run it that way. Pull the two intake bypass covers to have a better look at the pistons and rings. You can pull the intake manifold to have a look at the crank/rod/bearings.
Have you drained the gear lube? I suppose it is possible that the gearcase is jammed up also causing it to bind while rotating…

[billy-j]

Yes I planned on splitting the crankcase and asses for water rust damage on crankshaft, bearings, reeds etc. My original question was if I could keep the piston rings in the exact order they came off the piston cleaned them up, cleaned piston and piston groove’s and if cylinder cleaned up with a light hone can they be re used satisfactory ? I never really bothered to fix a seized motor before to many good low hour engines in Ohio to be had. I would think if every thing regarding piston rings was assembled the way it was originally with a light hone they would just re seat themselves. Maybe I am wrong. Opinions please. Thank You Bill,

[labrador-guy]

billy-j wrote:

Yes I planned on splitting the crankcase and asses for water rust damage on crankshaft, bearings, reeds etc. My original question was if I could keep the piston rings in the exact order they came off the piston cleaned them up, cleaned piston and piston groove’s and if cylinder cleaned up with a light hone can they be re used satisfactory ? I never really bothered to fix a seized motor before to many good low hour engines in Ohio to be had. I would think if every thing regarding piston rings was assembled the way it was originally with a light hone they would just re seat themselves. Maybe I am wrong. Opinions please. Thank You Bill,

Bill you motor needs to be evaluated when you get it apart. If you can get the rings off the piston without breaking them you can slide them back into the bore to see what the end gap is. That will tell you how much wear it has. Look for scoring and deep scratch marks on the piston and the bore wall. If you have your engine all apart you sure don’t want to do a half S job on it! Pistons and rings are available, seals and gaskets too! The engine will tell you what it needs, the decision you need to make is how much moo-la you want to put in it!

dale

get’em wet….don’t let’em set!

[fleetwin]

And don’t forget to drain the gearcase before getting started with the powerhead…. A gearcase full of water/rust is a big cost repair as well..

[Bob Wight]

fleetwin wrote:

And don’t forget to drain the gearcase before getting started with the powerhead…. A gearcase full of water/rust is a big cost repair as well..

Yes, indeed. You don’t want to find this when you open your gearcase.

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1955 Johnson QD-16
1957 Evinrude Fastwin 18
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."

[billy-j]

Thanks for all the replies friends.I always take engines that I work on completely apart and inspect each part and replace all defective or broken components. Reseal lower units, water pump impeller, coils ,condensers etc. I was curious what the consensus was regarding unsticking a seized motor and re using the piston rings if within spec’s. Living here in Ohio near Lake Erie this part of the country is the epicenter of old outboard motors. All fresh water and usually low hours because of our shorter boat season. I never had to un -stick a seized motor. too many good ones around for cheap. I have some like this but do not want to dump a ton of money in them. I would give them what they need but it’s way easier if power head is bad just to find another motor that fell over and broke a bunch of parts get it for little $ and just use the power head off it and sell what’s left. Like Labrador guy said how much moola $ you want to spend. Regards Bill,

[Bob Wight]

You are fortunate to have the ability to source big replacement parts (powerhead, gearcase) in your area. If you routinely tear yours down anyway, open this one up and see how it looks. If the cylinders look they can be salvaged, then just do a hone job and see how they come out. If I were going so far as to tear it down and do a hone job, I would probably put in new piston rings.

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1955 Johnson QD-16
1957 Evinrude Fastwin 18
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."

[Author]

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