Topic: ’57 35hp flywheel compatibilities – Antique Outboard Motor Club,Inc

This topic has 8 replies, 4 voices, and was last updated 9 years, 4 months ago by johnyrude200.

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September 12, 2016 at 3:54 pm #5240
johnyrude200
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Hello,

I have a flywheel with bad stress fractures I just pulled needing replacement. Casting is 580232-2. Now M.E. and others do not have this number. Even my original hard copy parts books don’t list this. Ebay searches show several of these available, less the ‘dash 2 [-2]’ suffix. A few listings show this also being on a later 40hp motor.

Question is – are these going to be compatible? I heard a couple of mechanics lament about how these flywheels went through a degree change or two in the magnet placement in the 50’s (not sure if this is TRUE OR NOT), so wanted to ask the panel prior to making the investment. The story was, they replaced the flywheel with another seemingly same unit, only to realize after hours of ghost chasing the magnets are located slightly different making the motor not run/be erratic.

Thanks!
September 12, 2016 at 5:07 pm #43887
beerman57
Participant
jr200 – check your PM box.
September 12, 2016 at 5:31 pm #43888
frankr
Participant
True, they made so many changes in those days, mortal man was left in total confusion. Four main considerations are keyway length, taper size, generator pulley, and reinforced hub. This service bulletin was sent to Gale dealers, but Johnson and Evinrude dealers got their respective versions also.

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September 12, 2016 at 8:24 pm #43907
johnyrude200
Participant
Well that helps. This is probably an original ’57 flywheel. No "Q" stamped in, and for that matter, no notches for emergency rope starting. The cracks are physical metal breaks, not just hairline cracks.

I suspect removal of the flywheel over the years for service has eventually caused failure, but who knows. There is basically a triangular ‘chunk’ that is cracked connecting all 3 puller orifices; and it’s a good thing the motor was not attempted for service prior to being brought to me by the customer. It’s bad enough where you can basically SEE into the cracks, so it’s ready to let loose. The puller orifices are pretty well stripped out too.

I’m just glad the puller was able to get it to pop off the crank before it completely failed! Had that happen before once! Motor has 120/120, and everything else appears to be in good working order otherwise! (just needs the points cleaned/re-synced)
September 19, 2016 at 11:25 pm #44340
johnyrude200
Participant
Well I’m up the river with no paddle again. Just received a 1960 40hp flywheel compliments of ebay, only to find that the flywheel keyway is different. The rest of the flywheel at the casual glance appears the same as the ’57 version. The casting number is the same too on both.

My question – is there a difference in the woodruff key between these two motors, so if I were to switch out flywheel keys, would this allow the newer flywheel to fit on this motor? The cranks come back as different numbers in the parts books.

The newer flywheel sits about a 1/4 too high on the ’57 crank, and the taper on the newer flywheel is shallower compared to the ’57 flywheel.

Thanks
September 20, 2016 at 12:24 am #44347
frankr
Participant
1960 flywheel used a shorter key in a different crankshaft. I’m thinking it is the same key as used on the smaller motors. Maybe not, I’d have to look up the number.
September 20, 2016 at 12:58 am #44352
johnyrude200
Participant
Well, the 18hp motors don’t appear to use the same key for that year (1960). I guess I’m wondering if this flywheel is even compatible with the older motor? Anyone out there had success?
September 20, 2016 at 1:15 am #44354
dan-in-tn
Participant
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Im with FranR. The short/small key is #307480. That is the most common key OMC uses on all motors. Still used today on 300hp G2 motors. The #302602 long key (used on the ’57 & others) is the oddball. NEVER rely on a cast number to get the same part. Especially when it is a rotating assembly. As the service bulletin points out a different hub was cast into the same outer part of the flywheel.
If you take the key out of the crank does the flywheel drop down far enough onto the crank? (You mentioned it was seating up a 1/4" too high?) Even if it does I would not feel comfortable using this flywheel on the motor. I mentioned before that OMC had some balance issues with these motors as horsepower went up. The 40hp was a tipping point. They had to go in & make the top of the crank bigger, but I suspect other things happened to stop the harmonics of the engine from fretting the crank to flywheel fit. Just my opinion, but I did hear it discussed. Other motors had some of these problems during my tenure at OMC.

Dan in TN
September 20, 2016 at 1:19 am #44357
johnyrude200
Participant
OK, I won’t go any further with this flywheel. Guess I’ll have to put it up for sale and hope to get my investment back! A little tough finding a replacement given the casting numbers are the same, less the letter "Q" on the top of it.

Those flywheel keys are the first ones I’ve seen (but again, this is the first older 35hp I’ve worked on). I have 7 of those long thin keys sitting here as N.O.S. in my inventory! Those suckers go for $16.00 each!
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