85hp force cannot get flywheel off!!!

Jtom7

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Feb 20, 2013
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I have an 85hp force 1988 and I have been trying to get the flywheel off for days now. I have soaked it in pb blaster ( supposed to be wd40 on steroids) I have a good puller and I have grade 8 bolts. I am tightening puller to so much force I have broken a grade 8 bolt and tapped the puller screw with a hammer and it still won't break free. I have even tried prying up a little on flywheel and or hitting it upward with a rubber mallet. I don't want to damage the flywheel and especially don't wanna damage crank bearings with so much pressure on the puller screw against crank but it just will not break free. Anyone have a little tricks or ideas because I've never met a flywheel this stubborn. I don't wanna use a torch to heat it cuz it may damage stator or something else. Any advice please!!!! I'm getting frustrated to a point where I want to smash the dang flywheel off and replace it and the stator if it breaks.
 

BonairII

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Jun 7, 2011
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2,727
Re: 85hp force cannot get flywheel off!!!

Put flywheel puller on and tighten down pretty well......spray with PB blaster.....next day tighten a bit more, and so on.


Or hit it with some heat. Heat shouldn't affect stator at all. You're not going to heat the flywheel enough for it to reach the stator at all.
 

jerryjerry05

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Re: 85hp force cannot get flywheel off!!!

Flywheel.jpgFlywhee2l.jpgFlywhee1l.jpgPicture 006.jpgPicture 007.jpg

I use a three jaw puller.
Install it,but lave the nut on so stuff doesn't go flying.
I install the puller,tighten down with an impact wrench,maybe a little heat?
Then hit the center screw with a 3# hammer.
It might pop off might not.
See pics of one that wouldn't???
 

Jtom7

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Re: 85hp force cannot get flywheel off!!!

Thanks for replies. I will try again with your ideas. That is quite a bit of damage to the flywheel, stator etc. I hope to avoid that :) thank you for sharing the pics. Seems a bit ridiculous for a flywheel to be so hard to get off. I had concerns about using a 3 jaw puller cuz I thought flywheel might break with that outer edge pulling. I am using a harmonic balancer puller which fits with 3 bolts in the middle of the flywheel and so far 1 of my grade 8 bolts broke. I will keep spraying it with blaster and try tightening every day. There's gotta be a better design made or something for flywheels cuz people need to be able to get them off to perform repairs and not have to fight with the darn thing for a week. So much work for one little step.
 

Frank Acampora

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Jan 19, 2007
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12,004
Re: 85hp force cannot get flywheel off!!!

Well, it is no consolation but sometimes the crankshaft nose and the flywheel hub rust together. Sometimes just the key is rusted but either condition makes pulling the flywheel a difficult job. It will fight you all the way.

An impact wrench does seem to help as the vibration of the hammering seems to loosen the wheel better.

I have also heated the center of the flywheel with a propane torch while the puller is torqued really tight. When it pops, it does so with a dramatic bang and will fly off the crank if the nut is not on. And as said above, it should not harm the stator.

You can re-tap the center bolt holes to 5/16. They will have more strength and will also not strip out as easy. Just be sure to use a bottoming tap so you can get as many threads as possible engaged.

Old Mercury flywheels were way easier to get off. the hub was splined and the flywheel was bolted to it with 8 grade 8 bolts. You did not need to pull off the hub to access under the flywheel.
 

jerryjerry05

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Re: 85hp force cannot get flywheel off!!!

I NEVER did get the end of the crank and flywheel seperated???/
 

gm280

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Jun 26, 2011
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14,585
Re: 85hp force cannot get flywheel off!!!

Thanks for replies. I will try again with your ideas. That is quite a bit of damage to the flywheel, stator etc. I hope to avoid that :) thank you for sharing the pics. Seems a bit ridiculous for a flywheel to be so hard to get off. I had concerns about using a 3 jaw puller cuz I thought flywheel might break with that outer edge pulling. I am using a harmonic balancer puller which fits with 3 bolts in the middle of the flywheel and so far 1 of my grade 8 bolts broke. I will keep spraying it with blaster and try tightening every day. There's gotta be a better design made or something for flywheels cuz people need to be able to get them off to perform repairs and not have to fight with the darn thing for a week. So much work for one little step.

I had the exact same issues trying to remove my flywheel off an old Johnson 40 HP engine. So after breaking two sets of regular grade bolts with a three bolt wheel puller, I bought grade 8 bolts and tried again. But I used a pneumatic impact wrench as well. I thought it was never going to come off but as I applied more and more torque, it finally popped off with a loud bang. I thought I broke it, but it wasn't broken. The reason the flywheel is so tight has to do with the actual taper between the two metals, the crankshaft and the flywheel. In essence it forms a joint exactly like a mortise taper joint used on so many industrial drill presses, lathes and such. They are machined so well that the taper forms an extremely strong holding joint without any sealants or glues or anything else. Truly amazing the tight fit that forms... I never used a puller that pulled from the edge of the flywheel. I would think that that type of puller would apply less pulling power then the three bolt type from around the center section...JMHO!
 

maverick974

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Jun 26, 2009
Messages
122
Re: 85hp force cannot get flywheel off!!!

I just went through this a couple of months ago. I had a 1984 Force. 85 hp and I needed to put a new stator on it. I tried and tried with the 3 bolt puller and I had it so tight that I knew I was going to strip the threads in the flywheel. I finally used the jaw puller and I just kept tightening and tightening. I figured at that point, what more damage could I do? I had to use a long bar in the wrench to get enough torque on the bolt but it finally popped off.
It was kind of scary how hard it was to get it to pop off but it came off with no damage to anything. Just make sure to keep the flywheel nut on there to make sure the flywheel doesn't land in your neighbors yard.
 

Jtom7

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Feb 20, 2013
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Re: 85hp force cannot get flywheel off!!!

For the record I also used a pneumatic impact gun to tighten the puller screw and it still didn't come off. I used a socket with a long breaker bar and tightened too to a point I couldn't tighten much more cuz puller screw looked like it was starting to strip threads! I worry about damaging the crank bearings with all that downward force from puller and me tapping puller screw with hammer. As of last night I gave up and pulled the power head with the puller attached. I was trying to follow directions in mercury manual but decided I could pull power head without pulling flywheel and stator. I still like, and am thankful for the ideas though cuz I'm sure at some point I will have to pull the flywheel to replace the stator but for now I guess I don't need to. What a serious pain in the balls this has been and a huge waste of time for this one little step. Really hope I don't have issues with stator but does anyone have concerns about damaging crank bearings with all that pulling too??
 

Jtom7

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Feb 20, 2013
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Re: 85hp force cannot get flywheel off!!!

Gentlemen, I took the power head to the guy that bored out my last motor and he broke the grade 8 1/4" bolts too so he drilled and tapped to 5/16" and then was able to tighten puller enough and got it off so had I listened to Mr Frank Acampora I would have been the one to get it off lol. Thankfully he didn't charge me but I'll kick him a few bucks when he is done honing a cylinder for me. Thank you all for your input and I'd like to ask another question: when I put the motor halves back together what type of gasket maker do u guys suggest? Previously my father used a adhesive gasket maker but I find that much different than what is inside the untouched parts of the motor that the factory used. I know force has a specific part number but its available so what do u suggest? Just any old gasket maker?? I don't think using adhesive gasket rtv is good because it was a pain in the butt to get separated because it was literally like glues together. Thanks for any input!!!
 

Jtom7

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Feb 20, 2013
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Re: 85hp force cannot get flywheel off!!!

Mr Jerry Thanks for the reply. That is the exact stuff we used before and I will use it again. I just didn't think it was the correct stuff to use because it is adhesive silicone rather than just a straight silicone and it seems very different from what mercury used but if you recommend it too then that's what I'll use. Thanks again and happy boating this season :)
 
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