Re: Cutting Off a Flywheel? 1974 Johnson 4HP
I WON... sort of...
It's been a while since I last posted... had issues with the boat that would have kept me off the water if not dealt with first.
In that time the fly wheel has been under tension of the puller.
I got the shouldered stripper bolts (part numbers available in an earlier post... thanks for that) and drilled and tapped three new holes evenly offset from the existing ones. I got a new bottle of propane, torqued up the puller and started to apply heat. After several minutes of heat I applied upward pressure on the flywheel with leverage from a stick. I then used a pneumatic hammer to apply downward force on the crankshaft. After several minutes of that, the hammer attachment was seriously deformed. I figured I'd give it a bit more tension on the puller with the Impact wrench.
Well... a little bit was too much and I pulled the threads out.
So...
I cut it off.
At that point the flywheel had two broken grade 8 bolts in it... had 3 relief holes drilled along the crank and had 5 extra holes drilled and tapped (and stripped) for pulling. There wasn't much left to lose. If you look close... you can see the holes and broken off bolts.
It took almost 3 hours to get it off. I started grinding which took a very long time with a good cut off grinder and a new disc. to get to the inside... near the crank, I needed to drill a series of holes to connect to the grinder cut (broke off another drill bit when the crank slipped and turned). the grinder couldn't reach the bottom of the outsideof the ring... so I cut as much as I could and used the pneumatic hammer with a chissel bit to crack the last part. I then used the same penumatic setup to pry open the crack... but it still wouldn't let go.
There was a point where I thought... "I might die... having never seen the underside of this flywheel". About then is when I got out the framing hammer and just let it have it. And finally... it gave in.
I don't think I've damaged any of the parts that I wanted to keep (I was going to redo the ignition stuff anyway... the reason for needing the flywheel off in the first place). The end of the crank is damaged... but I should be able to remove the last 1/8th of an inch and be ok with the remaining threads.
I will need a flywheel though... Anyone parting out an early '70s Johnny-Rude 4hp?
I'm all set for next time though... I might start of by showing what happens to flywheels that don't behave
