Unsticking a stuck flywheel

[crabb]

Hello all. I picked up an RD 16 and I can see through the flywheel that both coils are shot. Seems to be a good place to start for fixing weak spark. I removed the flywheel nut no problem, but haven’t been able to get the flywheel itself to come loose. I tried tapping (gently) on the crankshaft and prying with a longer flatblade. That didn’t work. I put some penetrating oil between the flywheel and the shaft to see if that helped but the tapping didn’t work after penetrating oil. Then I got one of those crows foot pullers, the hydraulic balancer pullers, and only managed to bend the bolts I used the first time around and then partially strip one of the threaded holes on the flywheel on the second attempt. https://www.youtube.com/watch?v=faI_fLS6QWU
Tried to follow those steps but I don’t think that’s the way to do it. I’m really hesitant to apply any heat to aluminum in general, and for fear of damaging the magnets in the flywheel.

I’m sure I’m not the first person with this question, but I couldn’t find any other threads in the forum after searching. Is there some bolt or attachment on the bottom of the magneto assembly I’m missing? I feel like I’m missing a step entirely with how stubborn this one is. Any advice is welcome.

[bobw]

A harmonic balancer puller often works OK but when it comes to the stubborn ones, nothing beats the OMC factory flywheel puller, part no. 378103. If you use the balancer puller, you need to use Grade 8 bolts and washers. First step now will be to re-tap the one stripped hole. Be sure you leave the flywheel nut loose on the flywheel so you don’t booger up the crank threads when you put maximum tension on the puller. And when you rap on the center bolt on the puller, pry upward on the outside edge of the flywheel and give the center bolt a good quick sharp rap, not just a light tap and not like you swinging for the fences with a 10 lb. sledge. It’s the shock associated with the sharp rap that breaks it loose. A little heat on the hub area is not going to hurt anything. Finally, some wheels are just really stuck and it might take a few days to eventually work it loose.

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1957 Evinrude Fastwin 18
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."

[frankr]

Heat can damage that one. They had some where the aluminum flywheel pulled off the steel hub.

[bobw]

My bad – I overlooked his stated model number.

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1957 Evinrude Fastwin 18
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."

[frankr]

Don’t tap oversize threads in the flywheel. Use a Heli-Coil. Why? because the starter ratchet is hardened steel and an oversize bolt won’t go through the holes which are almost undrillable.

[fleetwin]

Borrow the OMC puller from someone to do this job…Trying to substitute the OMC puller with some other rig will only damage engine parts, and injury to you and other bystanders….

[mercuryman]

Here is what I would do. Find a nut and bolt with same thread as crankshaft , thread nut on crank half way. Screw bolt in until its tight on crankshaft. Then run rope through flywheel openings and lift the whole weight of motor . Then hit bolt hard it will come loose. Its important all the weight (of motor) is on flywheel and the bolt is tight on end of crankshaft. Then you are driving crankshaft out. Some of you guys may think this foolish but it works.

[Author]

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