Help please Johnson FD-21R 1967

oldboat1

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I usually hand thread the bolts until lightly bottomed out, then back off slightly. (You can strip the aluminum threads in the flywheel if the bolts are too shallow, and they twist a bit in the process.) In any case, make sure the puller is square to the flywheel when ready to pull. Use washers under the heads if the bolts need to be adjusted to get them even -- likely want to use washers anyway to make sure the bolts fit securely in the puller (thinking of a steering wheel or harmonic balancer puller, and maybe less than top-of-the-line.) Leave the loosened flywheel nut in place on the top of the shaft to protect the shaft. Tighten the center bolt by hand until everything appears to be square and even, then crank the bolt down tight with a box or crescent wrench. Whack it once or twice with a two-lb hammer (my preference), then crank the bolt down a bit more if the flywheel hasn't come loose. Repeat as necessary.

The nut on the shaft will keep the flywheel from fully coming off, but it will pop with some force -- sounds like something broke if you haven't done it before.
 

Dawson130

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Feb 13, 2018
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Thanks! I’ve done it on a riding lawn mower before so I know what you mean by the popping sound. Thanks for the advice. Very helpful
 

Dawson130

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Feb 13, 2018
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I was not able to get the flywheel off the bolts started to bend and I stopped. I’m gonna try to tighten it back down and pull it again with new bolts. It came up a little bit but wouldn’t go past a certain point. Should I run the main nut back down and try again?
 

oldboat1

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Flywheel either lets loose -- or doesn't. Doesn't slide up a little at a time. Sure it's not actually loose, held on by the flywheel nut that was lightly in place?
 

racerone

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Oldboat----Are the threads in the flywheel steel or aluminum.----Or are the threads in the aluminum of the flywheel or the steel hub ?
 

oldboat1

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threads would be steel. Aluminum flywheel cracks and chips around the hole if things go wrong.
 

racerone

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When the nut is torked the flywheel taper is pushed down on the crank taper.----It expands and locks onto the crankshaft taper.-----With the proper hefty puller you tighten the center push bolt.----Then hit the push bolt with a 16 ounce ball peen hammer.----They then pop off on the second hit 99 out of 100 times.
 

oldboat1

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If you are using a harmonic balancer puller, it probably looks a little like a bronze gothic cross — hold the long end while tightening down the center bolt (keeps the smaller bolts from twisting). It sometimes doesn’t hurt to say a few meaningful words (sacred or secular.) And sometimes it works to just let it set after applying the most torque you can. You may hear it pop while you are off eating dinner.
 

Dawson130

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I think I’m gonna buy the actual puller made for this motor. Just to be safe.
 

racerone

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I started using the factory " universal puller " about 50 years ago.----Used on 2 hp motors up to over 200 hp motors.----Not cheap but has rarely failed to pull a flywheel off..
 

Dawson130

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So went to harbor freight and bought a 15 dollar puller kit. With little to no effort the flywheel popped right off! The coils and every thing underneath look brand new. Minus the plug wires. Can any one help me on the process of replacing plug wires because it looks like I have to take that plate off that mounts the coils and such. In order to loosen the brackets that clamp the wires in place. Also the screw underneath it that secured the speed linkage is very loose. Thanks in advance!
 

oldboat1

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What was going wrong with the original attempt at pulling the flywheel? (could be instructive)

Wires are 7mm with a solid core — differ from automotive wires. I get it at the local NAPA store, but you can find it at various places. Small engine repair shops are a good bet.

Good idea to replace everything part by part so you have the original assembly for reference, or take lots of pictures before disassembly. Clamps for the wires are on the underside as you suggest. A couple of screws serve double duty holding coils in place along with the plate.
 

Dawson130

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Feb 13, 2018
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I already have the parts. But my question is how to I gain access to the underside of it?
 

Dawson130

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Feb 13, 2018
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Also the old screw clamp that holds the motor to the transom was seized so I had to drill it out. I have the new one but have to tap new threads into the hole. What size should I use?
 
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