Siezed up while starting

Joined
Feb 10, 2007
Messages
9
175 Johnson o/b 1981 model #J175TXCIM
I have read all previous posts on siezed motors. Only two reasons were listed 1) lower gear unit or 2) piston siezed due to water in cyclinder. Alittle background.
powerhead remanufactured 2003. less than 100 hrs of running time on it to date. Never went more than 2 weeks without cranking motor and let run till warmed up. Always easy to start ran good no problems. Yesterday I hit the key one time motor hit did not crank.Hit it the second time and the flywheel was froze tight.Starter teeth had to be tapped down with hammer to disengage fron flywheel. I removed all spark plugs..checked prop in all three gears worked perfectly...while in neutral at first i got alittle movement with ratchet on flywheel nut...when the flywheel did move there is a sound of "like bones crunching" coming from under the flywheel in the armature plate area. After several small moves all movement stopped. Is there anything in this area that could stop the flywheel /crank from turning? when in gear i can't turn the prop...in neutral it spins freely. Is MM oil my only hope as i don't think the gears are bad.
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: Siezed up while starting

Howdy, Del.

Welcome to iboats. :)

Sounds like something in there is severely broke. I think it is unlikely that a piston siezed. On a cold engine it may have broken a rod or dropped a magnet, jamming the flywheel.

I would have to tear it down to say anything for sure. Start by removing the flywheel and looking for debris.

Good luck. :)
 

itstippy

Chief Petty Officer
Joined
Jul 17, 2003
Messages
548
Re: Siezed up while starting

Welcome to the boards, Del!

If it "seized" just from the starter trying to turn it then it's highly unlikely there's any serious internal damage. A magnet dropping off from under the flywheel, as JB suggested, is possible. It's probably not you're gut-wrenching money-draining "seized motor" anyway. A "bones breaking" sound from under the flywheel when you turned it by hand tends to rule out anything with the gearbox or engine internals. MM oil ain't any hope at all. Pull the flywheel and observe. You'll need a cheap "harmonic ballencer" puller from Harbor Freight or similar retail outlet (about $10) and three 4" long Grade 8 bolts 1/4" diameter and 20 threads per inch. The harmonic ballencer puller will not come with those bolts - get them at a decent hardware store. There's a very good chance you'll spot a broken part under there and be able to order a replacement part and bolt it back together yourself.

PS - You can use an impact wrench to remove the flywheel nut. After everything's fixed nice you'll need a torque wrench ro reinstall it. Proper torque is a must. You jam the flywheel with the starter teeth (you've seen how that's done already!) and torque the nut down to specs.
 

mikesea

Lieutenant Commander
Joined
Oct 1, 2006
Messages
1,830
Re: Siezed up while starting

I'm betting on the magnet too, seen it more than once,hope you feel better
 
Joined
Feb 10, 2007
Messages
9
Re: Siezed up while starting

itstippy said:
Welcome to the boards, Del!

If it "seized" just from the starter trying to turn it then it's highly unlikely there's any serious internal damage. A magnet dropping off from under the flywheel, as JB suggested, is possible. It's probably not you're gut-wrenching money-draining "seized motor" anyway. A "bones breaking" sound from under the flywheel when you turned it by hand tends to rule out anything with the gearbox or engine internals. MM oil ain't any hope at all. Pull the flywheel and observe. You'll need a cheap "harmonic ballencer" puller from Harbor Freight or similar retail outlet (about $10) and three 4" long Grade 8 bolts 1/4" diameter and 20 threads per inch. The harmonic ballencer puller will not come with those bolts - get them at a decent hardware store. There's a very good chance you'll spot a broken part under there and be able to order a replacement part and bolt it back together yourself.

PS - You can use an impact wrench to remove the flywheel nut. After everything's fixed nice you'll need a torque wrench ro reinstall it. Proper torque is a must. You jam the flywheel with the starter teeth (you've seen how that's done already!) and torque the nut down to specs.
 
Joined
Feb 10, 2007
Messages
9
Re: Siezed up while starting

Del said:
itstippy said:
Welcome to the boards, Del!

If it "seized" just from the starter trying to turn it then it's highly unlikely there's any serious internal damage. A magnet dropping off from under the flywheel, as JB suggested, is possible. It's probably not you're gut-wrenching money-draining "seized motor" anyway. A "bones breaking" sound from under the flywheel when you turned it by hand tends to rule out anything with the gearbox or engine internals. MM oil ain't any hope at all. Pull the flywheel and observe. You'll need a cheap "harmonic ballencer" puller from Harbor Freight or similar retail outlet (about $10) and three 4" long Grade 8 bolts 1/4" diameter and 20 threads per inch. The harmonic ballencer puller will not come with those bolts - get them at a decent hardware store. There's a very good chance you'll spot a broken part under there and be able to order a replacement part and bolt it back together yourself.

PS - You can use an impact wrench to remove the flywheel nut. After everything's fixed nice you'll need a torque wrench ro reinstall it. Proper torque is a must. You jam the flywheel with the starter teeth (you've seen how that's done already!) and torque the nut down to specs.
 
Joined
Feb 10, 2007
Messages
9
Re: Siezed up while starting

Thanks guys, I will get right on it. The bolt size for the puller really helped. I will let you know what i find under the flywheel ....Thanks again
Del
 
Joined
Feb 10, 2007
Messages
9
Re: Siezed up while starting

Hey fellas ya'll were right I think. When I removed the flywheel I found flywheel magnet fragments. Everything else was intact and tight.One maybe two magnets were totally destroyed and at least one more of the remaining 5 was missing a 1/4" x 1" chunk at its edge. The largest fragment was wedged at one of the coils.
So now what? Can I get the magnets off another 175 Johnson? Is any adhesives used? Do I replace all of them as a set? If I go new how much am I looking at?
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: Siezed up while starting

When you order new magnets from a dealer the epoxy comes with them. the others will probably pop off pretty easy. Pop them all off and reglue them all. The key is getting the flywheel clean before gluing them back.
 
Joined
Feb 10, 2007
Messages
9
Re: Siezed up while starting

Dhadley said:
When you order new magnets from a dealer the epoxy comes with them. the others will probably pop off pretty easy. Pop them all off and reglue them all. The key is getting the flywheel clean before gluing them back.

Thats what I needed...I really appreciate your help...
Del
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: Siezed up while starting

Anytime! Let us know how you make out. (As far as the repair goes....the other may be too much info)
 
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