Un stick my rings

I've got a 25 HP Evinrude with low compression on both cylinders.(64 top 30 bottom) I pulled the head and the side covers off. The cylinder walls look clean,no scratches. I think the rings are stuck on the pistons. Has anyone had any luck unsticking the rings and if so how? Ive been spraying them with penetrating oil and turning the motor over.

I never had the motor running. I was thinking about putting the head back on if the motor will start,running some Sea Foam throught it with the fuel. It's supposed to unstick rings. Any thoughts? Thanks Todd

not sure what the compression is supposed to be in that engine, it seems pretty low. When it comes to collapsed rings and things of that nature, it's kind of a shot in the dark on working them out. The only luck i have had is just loading the cylinders up with some wd40 and getting it running long enough to heat it up good and then cool it off, maybe a few times. then do another compression test. However you don't have very good compression at all... not sure how that will turn out for you?

Figure I'd give it a try before I pull the pistons.

Sea foam. Do search for decarbonizing. Take a one gallon fuel can add 3/4 of a can of sea foam then fill with fuel oil mix. Put the leftover sea foam in a small spray bottle and spray in the carb as the motor runs. It will smoke like a mother.

Since the cylinder walls appear okay you may want to do one or more checks on that engine. You can pull the intake by-pass covers and take a look at each piston and rings on the intake side and (a little harder) you can also remove the exhaust cover and look at the exhaust side, which is more likely to stick. BTW, if the exhaust cover on the engine is toasty brown from a previous overheat you may be out of luck on reviving the engine without machine work and new oversized pistons....but lets proceed anyway.
Now...........instead of everything that has been mentioned already, go to a dealer and get some BRP Engine tuner or the Merc or Yamaha equivalent and do it right! If the engine will start then start it and let it warm up, bring up the RPMs and start shooting the tuner through the carb until the engine runs extremely rough, spray enough to keep it running this way until the can is around half gone. When the can is around half gone shoot enough in there to kill the engine and let it sit overnight then restart. You may need to do this more than once so use the rest of the can and repeat the process again if needed. That is the manufacturers recommended way to do it and I have done it this way with great success for too many years to count. These chemicals are specifically produced for what you are describing, are very powerful, and are wicked good! To prove this point, when you restart the engine take a look at the water and exhaust that exits the engine and you will be amazed at what comes out. Cross your fingers on not having more issues than stuck rings. The visuals I mentioned earlier will help tell the story.

Could also be a blown head gasket which is a cheap easy fix.

I pulled the head off it's the rings. they're stuck to the pistons.The head gasket looks fine. I've got to order some of that BPR cleaner. Thanks for all the advice. Todd

If it was me I'd go ahead and pull the motor apart and go through it just to be safe. A snagged ring can be real bad if it isn't taken care of quickly. Think of it like this, a Clymers Shop Manuual is alot cheaper then new pistons, rings and a fresh boring. Just my opinion.

The more I think about it,I think I'm just going to do a total rebuild on the motor. I've never rebuilt an outboard motor before,so it will be a learing experience. Todd

I would try some transmission oil first. If you have the head taken off lay the engine horizontal and pour some in each cyl and and rotate the engine over a few times, repeat this this a couple of times,then let it sit for a few days. If your head gasket is still in good shape, wipe the oil out and torque it back down and check compression. Make sure your gauge is right by checking it against a something that shows a good reading. Transmission oil has excellent solvent properties to it and will sometimes free-up the rings by dissolving the carbon. If it doesn`t work, time for a ring job!

Hey guys, hows things going? Really dig this site. If I meet someone and we start talking about boats I give them this site. Now, on to business. I just bought a 1984 Mercury 25XD, gave $600.00 for it. The motor will crank and run but has a hard time ideling and doing it smoothly. Its a used engine. Compression is great. 115-110. Its used..I knew I was going to have to work on it. I'm debating having the carbs rebuilt and the necessary adjustments by a shop. The carb on the engine has the fuel pump built into the carb. Never seen this before and its what's driving to have a shop do it. Then I read about this sea foam? What is this stuff? The guy at the shop told me about this Marine Engine Tune-Up and decarbonizer. Its a spray and told me how to use it on my carb. I also got the updated 2+4 for the fuel tank. Is sea foam better than the tune-up? Anyone have any ideas?Thanks for your help!!!!