1952 Johnson Seahorse RD12 25 HP - Removing Flywheel and Source for Ignition Parts

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1949 Penn Yan
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1952 Johnson Seahorse RD12 25 HP - Removing Flywheel and Source for Ignition Parts

Postby 1949 Penn Yan » Sun Aug 12, 2018 12:18 pm

Hello,

I have weak/intermittent spark, and I'm trying to remove the flywheel in order to get at the points, condensers and coils. 2 questions:

1. Using the factory recommended method of a strap wrench on the flywheel, I am unable to loosen the nut. The strap wrench is doing it's job - it doesn't slip - it's just that, as the flywheel is not locked in place, the inevitable small amount of movement when torquing on the flywheel nut is preventing me from loosening the nut.

Factory spec on the nut is 100-105 ft. lbs. The nut is clean and does not appear to be rusted. I soaked it overnight with penetrating oil and heated the nut, but to no avail. If only I could lock the flywheel in place. Suggestions?

2. I would appreciate guidance on a source for replacement points, condensers and coils.

Many thanks, in advance.

Cheers,

John
1949 Penn Yan Seagoer Trailboat
1952 Johnson Seahorse RD12 25 HP

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Buccaneer
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Re: 1952 Johnson Seahorse RD12 25 HP - Removing Flywheel and Source for Ignition Parts

Postby Buccaneer » Sun Aug 12, 2018 12:32 pm

I'm guessing you don't have an impact wrench, but that
would be my first choice. Interesting, but the specs on
my RDE-17, 25 hp, said flywheel nut torque 60 to 65 lbs.
I believe it was my grandfather that taught me when
trying to remove a nut (usually rusted) to use two
equal weight hammers and hold one hammer against
a flat on one side firmly, the using the other hammer,
smack the flat on the opposite side. It's worked for
me many times, but unless you're good with a hammer,
bad things could happen. :o
Some quick heat from a torch might also aid in removing
the nut.
If you can't hold the flywheel with the strap wrench
to use a breaker bar, with a "cheater" extension if necessary,
you might find a way to clamp the flywheel from turning,
or using a piston stop in a spark plug hole.
Good luck!

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Bob D
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Location: Staten Island NY

Re: 1952 Johnson Seahorse RD12 25 HP - Removing Flywheel and Source for Ignition Parts

Postby Bob D » Sun Aug 12, 2018 12:35 pm

Get an impact gun, prices are relatively inexpensive,or take it to your local auto repair. They can shoot it off in a second.
Parts are available, being a 52 you might have to dig a bit.Google the parts manual for your motor, and get the part numbers. With that you can search the internet.
I would also try Dan Gano at Ganotech,MarineEngine and EBay. I'm sure others will chime in for their favorite parts source.
Bob D

FrankR
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Re: 1952 Johnson Seahorse RD12 25 HP - Removing Flywheel and Source for Ignition Parts

Postby FrankR » Sun Aug 12, 2018 12:39 pm

Hm-m-m-m, don't understand why you can't hold the flywheel. But anyhoo, the torque to tighten the nut is 60-65 ft/lbs on your 1952. Aftermarket ignition parts have been getting a lot of bad press lately. You probably should get OEM parts from an Evinrude dealer, or at least another source selling OEM parts. That would include several members that you may hear from.

Chris_P
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Re: 1952 Johnson Seahorse RD12 25 HP - Removing Flywheel and Source for Ignition Parts

Postby Chris_P » Sun Aug 12, 2018 1:08 pm

As stated, a good impact gun should make quick work of that nut. You don't even really need to hold the flywheel, the impact gun just zips the nut right off. Then, of course, you will need a harmonic balancer puller with grade 8 bolts to actually remove the flywheel.

For ignition parts, post a wanted ad here in the classifieds. There are many members that will be able to help you out.

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Garry in Tampa
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Re: 1952 Johnson Seahorse RD12 25 HP - Removing Flywheel and Source for Ignition Parts

Postby Garry in Tampa » Sun Aug 12, 2018 1:50 pm

You don't really need a strap wrench to take off the nut. The inertia in the flywheel will keep it from turning while you give the wrench a swift smack with a heavy hammer. . . ;)
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kirkp
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Re: 1952 Johnson Seahorse RD12 25 HP - Removing Flywheel and Source for Ignition Parts

Postby kirkp » Mon Aug 13, 2018 9:36 am

Maybe it’s because it’s early so I may be missing something. The way I read the original post it sounds like the strap is holding the flywheel but the nut spins when trying to loosen it. Could the key be sheared allowing the shaft to turn in the flywheel?
Kirk

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Tubs
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Re: 1952 Johnson Seahorse RD12 25 HP - Removing Flywheel and Source for Ignition Parts

Postby Tubs » Mon Aug 13, 2018 9:41 am

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Last edited by Tubs on Thu Aug 16, 2018 9:50 pm, edited 1 time in total.
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1949 Penn Yan
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Re: 1952 Johnson Seahorse RD12 25 HP - Removing Flywheel and Source for Ignition Parts

Postby 1949 Penn Yan » Mon Aug 13, 2018 8:43 pm

MANY thanks for all of your replies:

1. Flywheel Torque: I mistakenly read 100-105 lb. ft. in my factory service manual for RD 22 series and up as 22 HP and up. Factory spec is indeed 60-65 lb ft, with thanks for catching that.

2. Removing Flywheel: "You don't really need a strap wrench to take off the nut. The inertia in the flywheel will keep it from turning while you give the wrench a swift smack with a heavy hammer."

Ding ding ding! Thanks Gary for such an elegant, simple solution! I inserted the plugs to provide compression resistance, and gave the wrench a gentle whack with my mallet, and it loosened instantly. I then used my puller to pop the flywheel off and all looks good.

3. Ignition Diagnosis and Parts: The reason I'm doing this is that the bottom plug has no spark, and the top plug has intermittent spark. Plugs are NOS Champions (I also tried the old Champions, which were known good plugs - to rule out the new plugs). Points were cleaned and gap is correct. Everything is clean with no corrosion.

I'm prepared to throw parts and money at this, replacing both sets of points, condensers, coils and plug wires, if needed. Unless one of you has a more thoughtful approach to diagnose the faulty components. Any other suggestions for favorite parts sources (to add to Bob's recommendations)?

Thanks, once again, in advance of your guidance.

Cheers,

John

FrankR
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Location: Florida

Re: 1952 Johnson Seahorse RD12 25 HP - Removing Flywheel and Source for Ignition Parts

Postby FrankR » Tue Aug 14, 2018 7:23 am

How about a picture? What do the coils look like? If they are cracked, they are shot, no doubt about it. If they look like an old dried up prune, they are probably shot.

Assuming good coils, 90% of ignition problems are dirty or corroded points contacts.


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