'75 Evinrude 6hp cylinders stuck

[Master Chief Rob]

Can anyone suggest an easy way to get unstuck?

 

[tx1961whaler]

Re: '75 Evinrude 6hp cylinders stuck

There are a few reasons why they can be "stuck"
1. The pistons are rusted in the cylinder. This could be a major or minor problem, depending on whether it is from sitting for years or if there was severe water intrusion from a blown head gasket or exhaust cover.
2. The lower unit (gearcase) is locked up. Remove it to see if the flywheel turns afterwards.
3. The coils have come loose under the flywheel and they are binding up the flywheel.
4. Severe catastrophic failure like a broken piston rod, crankshaft, etc.
5. Anything else that I forgot.

 

[Master Chief Rob]

Re: '75 Evinrude 6hp cylinders stuck

Knowing the older gentleman I got it from, I'm guessing it just sat for years without being used. I've tried to bump the prop with it in gear, but so far no luck. Any other suggestions?

 

[tx1961whaler]

Re: '75 Evinrude 6hp cylinders stuck

The only other suggestion:
Don't guess. Remove the lower unit and see if it turns, then if that does nothing remove the head and see how bad it is.
You can also try setting the motor on its front (spark plug holes up) and spraying the inside of the cylinders with penetrating oil like PB Blaster to see it it work something loose, but it's pretty easy to jack around and break the rings off doing this.

 

[boobie]

Re: '75 Evinrude 6hp cylinders stuck

Lay the mtr down with the cyl's facing up, take out the plugs , mix up some ATF and Acetone 50/50 and put in the cyl's. Leave set for a day or two and try rocking the flywheel back and forth with a strap wrench. DON'T use the flywheel nut.

 

[Master Chief Rob]

Re: '75 Evinrude 6hp cylinders stuck

Good info and tricks of the trade. Thanks for sharing...will try all the above.

 

[Master Chief Rob]

Re: '75 Evinrude 6hp cylinders stuck

Lower unit meaning entire foot or just the bottom half of the lower gear box at the prop?

 

[tx1961whaler]

Re: '75 Evinrude 6hp cylinders stuck

Entire foot. The drive shaft will come out with it.

 

[cajuncook1]

Re: '75 Evinrude 6hp cylinders stuck

This link will provide a lot of very good and useful information. Please remember to remove the spark plugs when rotating the prop or flywheel by hand to prevent accidental starting. It is also a lot easier as well.

http://www.sschapterpsa.com/ramblings/OMC_6hp.htm

 

[Chinewalker]

Re: '75 Evinrude 6hp cylinders stuck

If it were my motor and I was planning on using it for any length of time, I would take the time to tear it down and FIX the issue, rather than just soaking, twisting and beating on things. Just because you free it up doesn't mean it is "fixed". A rusted bearing can turn your motor into scrap metal in short order...

 

[SeaKaye12]

Re: '75 Evinrude 6hp cylinders stuck

THANK YOU Chinewalker.....!

I read so many posts on here about stuck motors that have been "freed up". I guess some do go on to run flawlessly for years...but if the pistons are rusted stuck...who's to say that the bearings aren't in a similar state. I'd hate to run one in that condition...I'd forever be listening to every sound it made...fearing that it was destroying itself.

Chuck

 

[itsaboattime]

Re: '75 Evinrude 6hp cylinders stuck

If it were my motor and I was planning on using it for any length of time, I would take the time to tear it down and FIX the issue, rather than just soaking, twisting and beating on things. Just because you free it up doesn't mean it is "fixed". A rusted bearing can turn your motor into scrap metal in short order...

amen

 

[Silvertip]

Re: '75 Evinrude 6hp cylinders stuck

Tip #1: As mentioned, soak with any of the concoctions mentioned.
Tip #2: Walk away for one week (that means do not even try to turn the engine).
Tip #3) Using a socket on the flywheel nut, "try" "gently" to turn the engine by "gently" rocking the socket clockwise and counter clockwise.
Tp #4: If the engine doesn't move, spray again and walk away for another week. Let this stuff do its job.
Tip #5: Repeat Tip #3.
Tip #6: At some point the engine will turn, even if a very small amount, do NOT try to force it "over the hump" so to speak. Contin ue to rock it back and forth. When progress stops, add more juice and walk away.

At some point the engine will be totally free and you will not have broken rings or ring lands on the pistons and you will not have damaged the cylinder bores any more than they already are. You can then set each cylinder on the bottom of the stroke and look into the spark plug hole with a pen light to see what the cylinders look like. Or just remove the head and inspect. All it costs is a head gasket.

 

[Master Chief Rob]

Re: '75 Evinrude 6hp cylinders stuck

Serious thanks to all. I've about spent all I can afford to at the shop, but don't want to trash it just yet. I'll give it a try and see what happens.

 

[Master Chief Rob]

Re: '75 Evinrude 6hp cylinders stuck

Thanks for the article. I'm sure it will come in hand many times!

 

[cajuncook1]

Re: '75 Evinrude 6hp cylinders stuck

Master Chief Rob, I sent you a PM (Private Message), please check.

 

[twocyclemania]

Re: '75 Evinrude 6hp cylinders stuck

I recently picked up two motors that were 'frozen.' One was an air cooled 61 Elgin 2.0. The other a 60's Scotty 3.6. Both are up and running great as I write this. I'm not a genius and some here will probably frown on how I did it but anyway here's what I did. Both were 'fiilled' with penetrating oil for a couple weeks before even attempting anything. With the air cooled I put the head on the ground with the lower unit removed. I put the driveshaft back into the head; clamped on a vice grip to the driveshaft and tapped it back and forth with a hammer. It gradually loosened and now after many times tested it runs great. With the 3.6 Scotty I took the intake off (behind the carb) and used a teflon pin about an inch in diameter (wood or anything fairly soft will do) to tap on the flywheel counterweights (the heavy part of the flywheel). After tapping (don't be a caveman) it loosened up and was home free. Some may cringe at what I did but it worked. In both cases you have to consider the amount of force as your dealing with bearings and parts not intended to be beat to death. Also, never, never, use the nut on the flywheel to attempt to loosen up a motor (snap goes the crank).

 

[oldybutagoody]

Re: '75 Evinrude 6hp cylinders stuck

Tip #1: As mentioned, soak with any of the concoctions mentioned.
Tip #2: Walk away for one week (that means do not even try to turn the engine).
Tip #3) Using a socket on the flywheel nut, "try" "gently" to turn the engine by "gently" rocking the socket clockwise and counter clockwise.
Tp #4: If the engine doesn't move, spray again and walk away for another week. Let this stuff do its job.
Tip #5: Repeat Tip #3.
Tip #6: At some point the engine will turn, even if a very small amount, do NOT try to force it "over the hump" so to speak. Contin ue to rock it back and forth. When progress stops, add more juice and walk away.

At some point the engine will be totally free and you will not have broken rings or ring lands on the pistons and you will not have damaged the cylinder bores any more than they already are. You can then set each cylinder on the bottom of the stroke and look into the spark plug hole with a pen light to see what the cylinders look like. Or just remove the head and inspect. All it costs is a head gasket.

Sometimes, like the Tinman, these old motors can be brought back to life with a little time, and lots of oil. This method has worked for me 2 out of 3 times. The time it didn't work ended up being a worn/rusted rod and crank on a motor that had been submerged. That motor has become a parts motor. I agree that removing the head makes it a lot easier to inspect the cylinders and pistons. You can also have a look at the condition of the rings by removing the intake port covers. You're probably going to order at least a few parts if you do get it lubed up and moving freely so just order a head gasket too. They aren't that pricey and it might even improve your compression.

 

[raczekp1]

Re: '75 Evinrude 6hp cylinders stuck

in this week i got 6hp 68' in good shape except he was frozen.
apply carosene with acetone in cylinders, i manage to unstack,

pulled of the head but rings was stack in grooves.

soak few days with carosene and acetone and new head gasket-motor fired up and runs good

 

[Mas]

Re: '75 Evinrude 6hp cylinders stuck

Lay the mtr down with the cyl's facing up, take out the plugs , mix up some ATF and Acetone 50/50 and put in the cyl's. Leave set for a day or two and try rocking the flywheel back and forth with a strap wrench. DON'T use the flywheel nut.

I just bought a seized Johnson 5.5 hp motor (CD19) for $50. The owner said that it seized while running. I was thinking impeller failure, stuck thermostat, or plastic bag on the foots intake. Anyway, I got some PB blaster and leveled out the cylinders with the spark plugs pointing upward, and soaked the cylinders with the PB and let it sit for 1/2 of a day. I came back and lightly tapped the pistons with a wood dowel through the plug holes, grabbed the flywheel with my hands, and gave her a good spin... bingo, free as a bird. I sprayed some more lubricant in the cylinders and cycled her through some revolutions. I tested the spark and got a really hot spark on both cylinders. I hooked her up to a fuel tank, and she fired right up and idled & reved great with no noise for hesitations.

Moral to the story...there's hope.

Mas