Johnson 1957 18hp Flywheel Problems

[frankr]

An 18hp has the exact same taper as a 5hp. No reason that flywheel won’t pop off with enough pull. Well unless somebody Loctited it on. Or the key sheared and it spun and welded itself on. When you get your new G8 bolts & washers, screw them in 7/16", no more and no less.

[kennmatson]

I’d get some heavier bolts as those grade one or two stove bolts may distort the threads or break. Hardware stores don’t generally carry hardened bolts so you’ll have to try an industrial or automotive store. Kenn

[mr-asa]

Since you are buying new bolts anyways, try and get some shoulder bolts like these http://www.fastenal.com/web/products/details/26330 they will let you thread in only enough to engage the threads and help prevent you from damaging the coils. They are a little more costly, but it’s what the factory puller sets use.

Edit: please note, those are not the correct bolts, just an example of what you probably want to look for

[Steve D]

I’ve found that sometimes you can’t get enough torque while holding the flywheel strap with one hand and tightening with the other. Asking a friend to hold the flywheel strap while you put your efforts into tightening sometimes helps. Using a longer extension handle/breaker bar or slipping a piece of pipe over the end of the handle can give you a bit more torque as well. Also use upward force on the flywheel while you give the top of the puller bolt a sharp blow. I’ve used a pry bar like in the picture and whacked the bolt, turn the flywheel a little and whack it again, repeat all the way around if stubborn.
Edit: to be more accurate as Steve A W mentions below don’t "pry" but lift up to take out slack in crank…helps avoid damage to bearings, etc.

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[johnyrude200]

I’ve had flywheels before where the flywheel nut is so tight, I had to use a wrench on the nut with a 4 foot cheater bar, and then use my flywheel holder with another 4 foot cheater bar attached, and two people (one on each cheater bar) pushing in opposite directions. You want to talk about the amount of force we applied? I have a degree in biomechanics…the amount of newton/lbs applied that sucker had to be up into the 1,000’s, perhaps 10,000’s just to break the nut loose. And this was a 3hp JW series…..

Cheater bars and good holders, along with a heavy sledge, have worked so far for me. Some are MUCH harder than others to get to pop. To the point of others…the amount of force applied when you strike it is what makes it pop. Crank that puller down as far as you can until you see if flex, then give it a hard knock with a heavy sledge. A simple hammer doesn’t have enough mass to really deliver a good blow, unless you are swinging for the fences like David Ortiz (New England Reference), and in that case, you have a better chance of missing the puller bolt and hitting something else by accident. Mass x Velocity = Force. Heavy mass x less velocity = roughly the same force as lighter mass with higher velocity (there’s a lot more to it than that, but in simple terms that the way it works).

On a side note, it was my understanding that prying up on a flywheel was a big no-no as it is a great way to distort or damage the flywheel/taper. What does the official panel say about this? I have always avoided it and been able to get all of the flywheels off (albeit, some with a few more curses than others).

[Mumbles]

Try carefully using an electric or pneumatic impact wrench. It saves beating around the bush and gets the job done.

[Steve A W]

Johnnyrude200
You don’t pry up on the flywheel. You just take out the slack in the crank.

Steve A W

Member of the MOB chapter.
I live in Northwest Indiana

[rschiff]

"There comes a time in every man’s education when he arrives at the conviction that envy is ignorance; that imitation is suicide; that he must take himself for better for worse as his portion; that though the wide universe is full of good, no kernel of nourishing corn can come to him but through his toil bestowed on that plot of ground which is given him to till." Ralph Waldo Emerson

I don’t normally do quotes and certainly can’t say I know much about Emerson but that one seemed appropriate, and google is amazing.

After three weeks of fighting with this flywheel, getting the right puller, getting new bolts, spraying penetrating oil every night, making my own flywheel strap, torqueing and trying again and again and again every night, losing all hope………..I WIN!

I got that #$^@#%^&#@$%&#@$%@#$%^@#$% to come loose last night! Flywheel off! I WIN. I WIN. I WIN

I WIN.

Thanks to all for helping me get past this hurdle! Onward. ➡ ➡ ➡

Robbie

[david-bartlett]

The right tools and technique, along with appropriate language will get the job done.

[weedlessdrive]

Looks like the nut is still on crankshaft, I can’t tell. Get some shorter grade 5 bolts with washers and loose the stove bolts. You’re asking for trouble. Screw the puller down further closer to flywheel then tighten it. When it’s tight tap the main screw on the puller.

[Author]

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