Frozen 3hp Johnson

dreamen

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May 1, 2012
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I just picked up another project. This is around 1960 white 3hp Johnson. In really nice shape but has sat for 10 years. It is frozen solid. I have removed the head, soaked with penetrating oil in the cylinders for a couple days. Tried a wood dowel and hammer on the pistons but did not use a lot of pressure. Do you think it is the rings frozen to the cylinder or? Any suggestions on how to free it up?
 

nwcove

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May 16, 2011
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6,293
Re: Frozen 3hp Johnson

I just picked up another project. This is around 1960 white 3hp Johnson. In really nice shape but has sat for 10 years. It is frozen solid. I have removed the head, soaked with penetrating oil in the cylinders for a couple days. Tried a wood dowel and hammer on the pistons but did not use a lot of pressure. Do you think it is the rings frozen to the cylinder or? Any suggestions on how to free it up?

Remove the lower unit just to be sure its not the problem.
 

racerone

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Dec 28, 2013
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38,501
Re: Frozen 3hp Johnson

Remove the exhaust cover to see how much corrosion is on the pistons.
 

boobie

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Re: Frozen 3hp Johnson

Try some ATF and Acetone mixed 50-50.
 

14 foot Starcraft

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Apr 24, 2013
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Re: Frozen 3hp Johnson

I bought a sea king 6hp that was "locked up" and I pulled the lower unit and it was all rusty so I did scrap the motor but I kept all the good parts after I started it with now lower unit and that means no cooling but the bottom cylinder was trashed more the less I just wanted to see if it would run lol. what happens is the gear lube leaks out and water leaks in then it locks up. if the lower unit is free turning then pull the exhaust cover and have a look see at the rings/pistons.
 

Chinewalker

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8,902
Re: Frozen 3hp Johnson

Tear it down. Only way to properly free up a motor is to get inside it for full inspection. Banging away on the pistons may free it up, but there are likely going to be rust ridges, watermarks and gunk that would need to be cleaned up. Those 3s are some of the best motors ever and worth doing right...
 

dreamen

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Re: Frozen 3hp Johnson

Not sure why my posts are not showing up? I will try some ATF and Acetone mixed 50-50 and let it sit for a week, pulled the lower unit and it was fine. Will pull the exhaust cover and see what it looks like in there and may just do a total rebuild. I have a carb kit just need engine gasket kit
 

14 foot Starcraft

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Re: Frozen 3hp Johnson

Not sure why my posts are not showing up? I will try some ATF and Acetone mixed 50-50 and let it sit for a week, pulled the lower unit and it was fine. Will pull the exhaust cover and see what it looks like in there and may just do a total rebuild. I have a carb kit just need engine gasket kit

Pull that exhaust cover so you can get oil on the pistons.
 

boobie

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Re: Frozen 3hp Johnson

Along with the oil soaking keep tapping the tops of the pistons with the wooden block or dowel.
 

dreamen

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Re: Frozen 3hp Johnson

I got the motor free up today. Was kinda a quirk deal. I kept putting atf and acetone in the cylinder and penetrating oil on the piston thru the exhaust port. I was able to move the piston with a wood block on piston and mallet. Never had to hit it hard but it moved a bit. I started taking the rest apart and put a puller on the flywheel and pulled on the wrench and it freed up the piston. Cleaned it up a bit and it spun like a top. I put my hand over the cylinder on the down stroke and there is good compression. I just do not know if the rings are frozen or not to the piston. The pistons look good as does the cylinder. The main bearings were not froze or it would not spin like it does. My question is should I tear it down and check the rings and put new gaskets in or leave it? If I tear it down have more questions later.
 

boobie

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Re: Frozen 3hp Johnson

Have you got the exhaust cover off ?? If you do look at the pistons and rings. Check the rings with a screw driver and see if they're still free.
 

dreamen

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Re: Frozen 3hp Johnson

It is hard to tell, they stick out a bit from the piston as you can feel a slight ridge from the piston. If they are stuck a bit they may free up once it is running again?
 

nwcove

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Re: Frozen 3hp Johnson

you should be able to see/feel the rings move when you push on them.
 

boobie

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Re: Frozen 3hp Johnson

Put the head back on it and see what kind of compression you have. If it does run you can do a good decarb on it.
 

14 foot Starcraft

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Re: Frozen 3hp Johnson

It is hard to tell, they stick out a bit from the piston as you can feel a slight ridge from the piston. If they are stuck a bit they may free up once it is running again?

stuck rings score cylinder walls. DO NOT stick a screwdriver in the rings the proper way to see if they are stuck on a two stroke engine is to remove the exhaust cover (you have/had it off) turn the motor back and worth and watch the gap between the piston and the rings in the ring groves, as turning the motor back and forth there should be slight movement between the rings and piston (basically rock the flywheel slowly back and forth looking at the gap between the piston and rings to open and close on ether end depending on if the piston is going up or down and if its super hard to see (ring grooves tight fit nicely) put some oil on the rings and watch for the oil to squish out from the opposite side the piston is moving)


I'm going to make you a video showing how to look at this
 
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dreamen

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Re: Frozen 3hp Johnson

I looked at the rings, used the oil, difficult to tell. Put the head back on and did a compression test. One of my testers was 50 one was 60. My compression testers are old. Not sure what the compression should be. Both cylinders were the same. Any body know what the point gap should be? There is a 1/2" screw plug just below the exhaust port cover, looks like a lubrication port? Should anything be done with that? Working on the carb, getting it cleaned the old cork float was coming apart and was really bad. The inside of the carb looks good. Will get it cleaned out and new gaskets and float and then put things back together if I do not split the case to work on the pistons? The cylinder and pistons look good, no residue or ridges and all carbon cleaned out of head, and exhaust port.
 

boobie

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Re: Frozen 3hp Johnson

Put it together and see what happens. JMO
 

dreamen

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May 1, 2012
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Re: Frozen 3hp Johnson

Got the motor together. 45 today and nice, just had to try it. Could not get my 55gal barrel out of the snow and found a softner brine tank in the barn, a square one use a short piece of 2x4 to strengthen the motor on the tank and filled up tank with water and motor with gas and oil about the 3 pull fired right up. As soon as I got the carb final adj ran strong on high, water pump pumping, impeller looked good but I think I am going to replace it with a new one. Rubber gets old. Got this to idle so smooth. Boy what a great feeling!! I have a great little motor that will lasts for years, grandkids with have so much fun with it on the old alumacraft boat. Not to bad for less than a $50 investment including parts. Thanks for all the help, it is much appreciated.
 
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