new to me 1970 Johnson 25hp tiller short shaft. locked up

[Roadking57]

Hi guys n gals! A friend from where I work gave me this motor free! He thought it was only needing the usual things after sitting in a garage for a number of years. After I brought it home I removed the cowling and found loose insulation packed around the whole inside! Made me chuckle a little. After removing the mouse hotel, I tried the pull rope but no go. I made sure it was in neutral and tried to turn the flywheel by hand, then slight press with a big screwdriver. wouldn't budge an inch. OK, removed spark plugs. Upper cylinder plug looked fouled with metal Lower plug looked normal. Peered inside with a light the upper cylinder/piston top looks corroded bad like as if a squirt of saltwater had been left in it. Lower piston looked rusty but smooth. I then squirted penetrating oil on the head bolts let it soak for about 20 min. then removed all but one that despite being as careful as I could and using a handwrench only, the head broke off kinda suddenly. I squirted more oil on it and then using a rubber deadblow mallet tapped and tapped all around the edges of the head and it wont budge. Im thinking its hungup on that broke off bolt. All the bolts I removed were heavily corroded with aluminum powder. I was hoping to slide the head off that broken bolt and remove it with a pair of vise grips with possibly a little heat. But so far I cannot get the head to let go. Don't wanna use heat on the aluminum head. I was able to remove the thermostat cover and old thermostat.
Has anybody dealt with a stuck head like this? Right now I'm thinking maybe a machine shop is my only hope. I haven't tried tapping a scraper in between the head and block yet. Was also searching for a used head in case this one gets destroyed. No luck there so far. Gaskets yes. Heads no, seeing alot of out of stock.

 

[racerone]

Use a propane torch !----Near that head bolt and head will loosen / rotate.------Remove bypass covers to look at pistons and rings.-----Motor likely needs complete tear down.

 

[F_R]

At least the price was right. "Free" is exactly what that thing is worth. All kidding and ribbing aside, yes, those stuck bolts are something we deal with daily here in salt-water country. You might have to get a bit violent with that head, depending on how bad it is. Use lots of heat if you have to. The main deal is cause as little damage as possible.

 

[Roadking57]

propane heat near the head is alright? I mean with restraint of course. I have oxy/ace as well.

 

[F_R]

Oxy/ace is better. You want to get it hot to do any good. Just don't melt it and you'll be ok. Like I said, it's a daily thing around these parts.

 

[Roadking57]

Good news! I got the head off! used several scrapers and some propane. At first the blue can of propane didnt seem to be working. I switched to map gas and she came off! I kept tapping the scrapers in while keeping the heat on that broke bolt. I almost gave up then the armor cracked sort to speak.

 

[Roadking57]

I also just found and ordered a service manual for this motor $18 U.S. should be here next week

 

[Roadking57]

Update!
I got her unlocked! Sprayed penetrating oil in the cylinders about every other day for a week. Used a breaker bar on the flywheel nut, and without a lot of force she broke free! I turned it until I got one piston all way down in the cylinder and scrubbed the walls with penetrating oil and scotchbrite a bit. Then the other. Turned it back n fourth making sure it felt smooth and then turned it all way around a few times. She is tight but smooth. Some light rust in the cylinders. Pictures soon.

 

[racerone]

If water was INSIDE on the roller bearings then there might be damage.----Pitting of crankshaft and connecting rods may have occurred.------Motor will run but for how long ?-----Removing bypass covers ( 4 screws each ) allows for a look inside the crankcase, may help you decide.

 

[Roadking57]

I knew the previous owners son. Worked with him a number of years. He told me it was stored in a barn inside a separate storage room upright on a saw horse. With the amount of dry loose insulation "mouse hotel" I don't think there was much if any moisture. I will be checking it out

 

[Roadking57]

Pulled those small covers off. Could see the rings. cant see much past pistons. So far everything looks okay. I took a rounded screwdriver and lightly put some pressure on the upper rings and got a tiny bit of movement just enough to let me know they don't seem to be stuck in the grooves.

Part of me wants to just rip and tear it apart. Get a boatload of new parts and go from there. Part of me wants to get it running and see how she does. From the history I've been told (I am the 2nd owner), It was taken care of and always ran good. Aside from the expected things like cracked wiring and hoses I'm seeing a good engine so far.

I sprayed the recoil start spring that was sluggish and stiff and yesterday it is now operating fine and springing back great. I think I want to go ahead and replace the rope. I can see it dry rotting in spots.

 

[Crosbyman]

Personnaly I would run it and see what happens .extra oiling or good decarb product won't hurt

my stuck hard 9.5hp took a week to loosen up... it has been running a few years now with no issues.

 

[ahicks]

Bored one day, I bought a "stuck" 90hp Honda, figuring I would be installing a used short block. Turned out the engine was fine. The LOWER UNIT was stuck! It didn't have a drop of oil in it, was totally full of water. That info turned what was going to be a PIA job into an easy peazy job!

 

[tphoyt]

Me too
Picked up a 28 Johnson for $50 that was locked up tight. It had been stored indoors but sat for 10 years. I figured I would take a chance at doing the least amount of work to see what would happen. Worst case scenario I would have $50 worth of spare parts. So I filled the cylinders with a mix of Diesel, ATF and Acetone let it sit for a week and after wrenching on it got it break free. Pulled the head and hit the cylinder walls with a scotch bright pad to clean them up. She fired up and ran great so I ran a few tanks with extra oil and she’s been going strong for 4 years now.
Best of luck which ever road you take.

 

[racerone]

When I worked at a Johnson dealer in the late 1960's it was not uncommon for a stuck motor to come in.----I used to ask the folks what happened.-----Often a wrench on the flywheel nut would loosed them up.-----They ran fine.------There were no 50 year old motors that came in for repair in 1968 !!!----Today I find motors that may have sat for 30 years.

 

[ahicks]

When I worked at a Johnson dealer in the late 1960's it was not uncommon for a stuck motor to come in.----I used to ask the folks what happened.-----Often a wrench on the flywheel nut would loosed them up.-----They ran fine.------There were no 50 year old motors that came in for repair in 1968 !!!----Today I find motors that may have sat for 30 years.

Amen to that! "It ran when I put it away".....

 

[Crosbyman]

EV & J motors are like EVeready rabbits.... they keep going and going.....

 

[racerone]

Johnson / Evinrude were simple ( not perfect ) motors in the 1950' and 1960's .-----The used stainless shafts and helical gears.-----Accurate gearcases that did not require shimming procedures..-----Simple carburetors and ignition systems.-----Simple electric shift on some models too.------They are only " simple " if you understand how they work and how to maintain them.----No need for fancy tools and $100 / hr dealer support. ----Many new motors come with many plastic and miniature electronic bits that can't be fixed.

 

[Roadking57]

I got my service manual today!!!!!!! Whoot!!

 

[Crosbyman]

RoadKing..

your 1970 25 hp is basically the big brother or cousin of the jw.cd.ad.fd.rd family of engines back to the early 50s

most of what you need to service it is available on utubes and Leroys and similar sites .Not meant to preach here but depending on your experience level take a look at these

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