My friend didn't spray oil into his outboard last year and now the piston is froze. I was trying tho think of a way to get it to move and one idea is to take out the spark plug and spray in ether (starting fluid). The replace the spark plug and connect wires to the housing and end terminal of the plug. Standing some distance away, and behind some protection, connect the wires to a battery making a spark. The explosion should move the piston, if it was frozen in the going down position, I think. Another way is to spray nut cracker into the pison area dn alet it do its thing, then try to move the piston using the starter. I like the idea of the explosion. Blow the whole thing up if it doesn't work. Any ideas other than these two for freeing a stuck piston? Is anything wortht he effort or is the motor junk? My guess is if the rust is too much, then the rings will be fused to the piston and the walls. yo might free tit from the walls, but not the pistons. He might have to replace the piston head, riongs, and resleave the unit, if it can be resleaved,
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Is your life insurance up to date?
The explosion is a sure way to kill the engine and maybe you. That approach will either blow off the head, or break the rod, either way the engine will die. Be careful of flying metal pieces. Suggest you take off the head and apply a liberal amount of penetrating oil and let it sit over night. Try to pull the starter cord with the head off to see if it is loosened. If not take a piece of wood, place it on piston head and GENTLY tap it to try and loosen the piston. If that doesn't work, repeat the oil and wait another day. OR BLOW IT UP and maybe you can become immortalized in the annual Darwin Awards. Russell
The explosion is a sure way to kill the engine and maybe you. That approach will either blow off the head, or break the rod, either way the engine will die. Be careful of flying metal pieces. Suggest you take off the head and apply a liberal amount of penetrating oil and let it sit over night. Try to pull the starter cord with the head off to see if it is loosened. If not take a piece of wood, place it on piston head and GENTLY tap it to try and loosen the piston. If that doesn't work, repeat the oil and wait another day. OR BLOW IT UP and maybe you can become immortalized in the annual Darwin Awards. Russell
Dont break the piston rings !!!!!!
If you *force* the piston you will surely break the piston rings. Remove the sparkplug and pour in 2 tablespoonfuls of Marvel Mystery Oil (automotive store). Let soak for a WEEK. Remove the pull rope starter recoil assembly, etc. and put a wrench/socket on the nut on the shaft that holds down the recoil assembly - this will be the stub end of the crankshaft. GENTLY and without FORCE rock the crankshaft back and forth - if it doesnt move add more MMO to the combustion chamber and let sit another week. If it moves add more MMO and GENTLY keep rocking back and forth until the pistion rings break free from the cylinder walls, etc. Keep rocking and adding oil until you can turn the crankshaft all the way through one rotation - DONT FORCE IT. If you are about to need force to move the crankshaft .... add more MMO and let soak. Once the piston is totallly free and can be hand turned without binding, then Add more MMO and 'spin' the engine many times by hand (sparkplug out) until the rotation is smooth and non-binding. Then and only then, start the engine and run at idle and NO LOAD until warm. Add more MMO to the combustion chamber and let soak a few days before repeating. What has happened is that water has gotten into the combustion chamber and the piston rings have frozen in the piston ring grooves. The MMO and GENTLE persuasion will break the rings free and repolish the surfaces. DONT FORCE a frozen piston as you WILL absolutely break the piston rings. Patience and liberal soaking of the combustion chamber with Marvel Mystery Oil will eventually break the piston and rings free.
If you *force* the piston you will surely break the piston rings. Remove the sparkplug and pour in 2 tablespoonfuls of Marvel Mystery Oil (automotive store). Let soak for a WEEK. Remove the pull rope starter recoil assembly, etc. and put a wrench/socket on the nut on the shaft that holds down the recoil assembly - this will be the stub end of the crankshaft. GENTLY and without FORCE rock the crankshaft back and forth - if it doesnt move add more MMO to the combustion chamber and let sit another week. If it moves add more MMO and GENTLY keep rocking back and forth until the pistion rings break free from the cylinder walls, etc. Keep rocking and adding oil until you can turn the crankshaft all the way through one rotation - DONT FORCE IT. If you are about to need force to move the crankshaft .... add more MMO and let soak. Once the piston is totallly free and can be hand turned without binding, then Add more MMO and 'spin' the engine many times by hand (sparkplug out) until the rotation is smooth and non-binding. Then and only then, start the engine and run at idle and NO LOAD until warm. Add more MMO to the combustion chamber and let soak a few days before repeating. What has happened is that water has gotten into the combustion chamber and the piston rings have frozen in the piston ring grooves. The MMO and GENTLE persuasion will break the rings free and repolish the surfaces. DONT FORCE a frozen piston as you WILL absolutely break the piston rings. Patience and liberal soaking of the combustion chamber with Marvel Mystery Oil will eventually break the piston and rings free.
bad idea
Ether sounds like a recipe for disaster. I try to pull the rope on my OB several times over the winter to keep thigs free. Never had any freezing problems.
Ether sounds like a recipe for disaster. I try to pull the rope on my OB several times over the winter to keep thigs free. Never had any freezing problems.
Won't work
If the piston is already at BDC, your little explosion is likely to do more harm than good. The other problem is that the explosion could escape through the valves. Path of least resisitance and all. 2 or 4 cycle? MMO is the best thing to try. WD40 is likely to gum up the works. WD40 is not a lubricant. I have also had luck freeing up pistons with hydraulic jack oil. Not sure why but an old timer turned me onto it and it worked. Tim R.
If the piston is already at BDC, your little explosion is likely to do more harm than good. The other problem is that the explosion could escape through the valves. Path of least resisitance and all. 2 or 4 cycle? MMO is the best thing to try. WD40 is likely to gum up the works. WD40 is not a lubricant. I have also had luck freeing up pistons with hydraulic jack oil. Not sure why but an old timer turned me onto it and it worked. Tim R.
This should work.......
I have had succes on more than one occasion with this . Remove the spark plugs and turn the motor so that the spark plug holes are up. Pour a liberal amount of mystery oil into the cylinders and let is sit for a few days. remove the cylinder head to get access to the pistons. Place a piece of soft wood on the piston in question and tap on it with a hammer. It should go..... As an insurance policy, I would check the compression. There is no actual value but, there should be no more than 10 % difference between each cylinder.
I have had succes on more than one occasion with this . Remove the spark plugs and turn the motor so that the spark plug holes are up. Pour a liberal amount of mystery oil into the cylinders and let is sit for a few days. remove the cylinder head to get access to the pistons. Place a piece of soft wood on the piston in question and tap on it with a hammer. It should go..... As an insurance policy, I would check the compression. There is no actual value but, there should be no more than 10 % difference between each cylinder.
thanks for the mmo info
I knew the explosion method would not work. I knew the WD-40 wouldn't either. I was not aware of MMO and will pass that info on. I was aware of pushing the piston with a block of wood, but agree that the rings should not be broken and any attempt at moving anything should be with restraint. Again thanks. It is a 2 stroke. If the boat was stored in Florida (St. Pete) inside the boat, why did the otor sieze up in the first place? High humidity? If so, I sure learned something here. His diesel siezed up too and he bought a replacement. He only knows how to start them and not much else. I was his repair techy but have other commitments so cannot go there to lend a hand. And he never called last year when he put the boat on the hard and asked for info on "winterizing" either motor. And he is a Miami born and raised person. Think he would know better if humidity is/was the problem. Moisture obviously was the problem, only I am not sure how it solidified the motor. This is the second time I herd of such a thing. Almost bought a bristol condition Grampion 35 for $15k because the motor was siezed. He sold it the day i arrived to take delivery, even after I sent him $5k as a down payment. The point is I now know things rust big time in Fla.
I knew the explosion method would not work. I knew the WD-40 wouldn't either. I was not aware of MMO and will pass that info on. I was aware of pushing the piston with a block of wood, but agree that the rings should not be broken and any attempt at moving anything should be with restraint. Again thanks. It is a 2 stroke. If the boat was stored in Florida (St. Pete) inside the boat, why did the otor sieze up in the first place? High humidity? If so, I sure learned something here. His diesel siezed up too and he bought a replacement. He only knows how to start them and not much else. I was his repair techy but have other commitments so cannot go there to lend a hand. And he never called last year when he put the boat on the hard and asked for info on "winterizing" either motor. And he is a Miami born and raised person. Think he would know better if humidity is/was the problem. Moisture obviously was the problem, only I am not sure how it solidified the motor. This is the second time I herd of such a thing. Almost bought a bristol condition Grampion 35 for $15k because the motor was siezed. He sold it the day i arrived to take delivery, even after I sent him $5k as a down payment. The point is I now know things rust big time in Fla.
He probably didnt allow time for the outboard to
totally drain when he removed it, put it piston top down on the ground, and the water simply back-filled from the exhaust section of the powerhead back into the combustion chamber. One shouldnt ever lay an outboard flat on the ground, always 'powerhead - UP'.
totally drain when he removed it, put it piston top down on the ground, and the water simply back-filled from the exhaust section of the powerhead back into the combustion chamber. One shouldnt ever lay an outboard flat on the ground, always 'powerhead - UP'.
Hey professor! That'd be you Rich.
Your posts have been spot-on. Just wanted you to know that some of us out here noticed.
Your posts have been spot-on. Just wanted you to know that some of us out here noticed.
Marvel Mystery Oil....
I second the notion on the Marvell Mystery Oil, I used it on old motorcycles, worked like a charm. It's also somewhat compatible with crankcase oil, so it won't do any harm there. If it's a four-stroke engine, change the crankcase oil asap after freeing the piston. Old bikers trick is Coca-cola, it's pretty corrosive (phosphoric acid) so it will eat through soft rusty metal and can free a seized piston as a last resort. The piston rings and cylinder walls will take some damage in the process, but it'll make it move again. Good luck, tell us how it goes. .-=gp=-.
I second the notion on the Marvell Mystery Oil, I used it on old motorcycles, worked like a charm. It's also somewhat compatible with crankcase oil, so it won't do any harm there. If it's a four-stroke engine, change the crankcase oil asap after freeing the piston. Old bikers trick is Coca-cola, it's pretty corrosive (phosphoric acid) so it will eat through soft rusty metal and can free a seized piston as a last resort. The piston rings and cylinder walls will take some damage in the process, but it'll make it move again. Good luck, tell us how it goes. .-=gp=-.
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