Method to repair damaged crank/ flywheel key?

[440roadrunner]

I'm kicking around "simple" (redneck?) but effective methods to repair a damaged crank/ key/ flywheel. Bear in mind I'm 73, "how much longer" can I use this?

I have an early Johnson 40hp with the so called 35 HP size crank taper. The keyway on both the crank and flywheel are damaged. I have another flywheel, but the crank may tear it up again. Looking for alternatives

What I'm thinking is to get it cleaned up, carefully install with the key, so it's properly located, remove nut, then drill (or mill) down the opposite side of the crank and flywheel, maybe? 3/16 or so hole to form a new "keyway" and then pin it with a short pin before reinstalling the nut

I have an old Jet drill/ mill, and pulling the powerhead is not that big a job.

 

[racerone]

Facts.------The key locates the flywheel for proper timing of the MAGNETO.-----The flywheel is driven by the locking tapers.-----Flywheel tapers must be lapped for proper fit contact.---Must be installed clean and dry.------Nut must be torqued to specification.-----So get a new factory key and lap the tapers.-----Machining new keyway might not be needed here.

 

[Scott Danforth]

agree on the tapers

if the key way is really buggerd and it bothers you. you can get enecon steel shaft repair epoxy. wax up a new key, use the epoxy, dress the repair to match shaft taper.

however the key way is there primarily so you align the crank and flywheel properly

 

[tphoyt]

These are good plans. I feel like either may do the trick. It’s worth a try you got nothin to lose right?

 

[racerone]

The fitting of the key and the flywheel tapers is much misunderstood.-----Did a 50 HP motor a while back.----After talking to owner and some quick checks I suspected a sheared flywheel key.------Yes it was and and the tapers had been greased.----No wonder it sheared !

 

[440roadrunner]

Well the crank may be damaged beyond lapping, but just how do you do that? After all the flywheel is much softer than the crank, so you are trying to "lap" two vastly different metals. I am somewhat reluctant to "burn" another flywheel and find later that the thing ate that one as well.

Maybe I should rethink--maybe this engine is not worth it, OR if a 35 is the same crank, I may sacrifice another 35 and go ahead and "dive in."

I'm well aware that the thing must be dry. In fact being greasy/ oily is maybe what caused this---before I ended up with it.


In an "anecdotal" moment, I have one 35 I just cannot believe--got it pretty cheap--when I pulled the flywheel it did not "pop" off--required a LOT of cranking on the puller. Someone had physically damaged the crank ??? pounded it with a chisel, ??? and the two pieces were a complete mess---so it needs a crank AND a flywheel

and O'course the other complication is that I have a mix of various engines, some of which are the older unsilenced leg and some are, so the powerheads do not interchange.

 

[racerone]

Good luck with your projects.----Lapping of the crankshaft / flywheel is a standard procedure.----Has been part of outboard repairs for some 50 years , perhaps more !

 

[440roadrunner]

Good luck with your projects.----Lapping of the crankshaft / flywheel is a standard procedure.----Has been part of outboard repairs for some 50 years , perhaps more !

So can you point to some recognized procedure? It is not in any manuals I possess...................

 

[F_R]

Usual procedure is patch it up enough to get it running, then sell it. P.T. Barnum was right.

 

[440roadrunner]

No I just do this for a hobby. If I can't fix this one it will become a "parts motor." Unfortunately 2 other 40's I have--one a long shaft--are the much hated electric shift. But one or the other may provide a power-head for this one.

 

[flashback]

Since you said red neck repair, de-grease it real good and then put some red locktite on the shaft when you put it back together. You may not ever get it off again so be sure all is good..