55 RDE-17, 25 hp, Power Head O-rings, etc

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Buccaneer
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55 RDE-17, 25 hp, Power Head O-rings, etc

Postby Buccaneer » Sat Jul 07, 2018 10:26 pm

I have been going thru items on the subject motor, i.e.,
starter, carb, magneto, which are now ready to go.
As long as all these items are off the motor, is it worth
it / recommended to pull the power head and replace
the o-rings on the upper and lower crankshaft?

The magneto was somewhat "oily".
I see the top has one o-ring, bottom two (different sizes).

I was thinking it would be nice to pull the power head
and clean and paint the corroded engine pan, but
not sure if I want to spend over $30 for one can of spray
paint, on a motor that I don't even know if it's a "keeper".
Anyone find anything close in a spray can for Sea Horse Green?
I see the lower unit has already been repainted, but the wrong shade.

I attempted to pull the engine over via rope to check
compression. The flywheel has a very poor "rope notch",
if that's what it even is, therefore I had problems getting
good pulls. Managed three poor pulls for each cylinder,
and ended up with 85 and 90 psi. I would think this engine
should be over 100 psi. What say you?
Is it any harder to pull the power head on this rig than
one of it's smaller brethren, other than the extra weight?

Thanks
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RDE-17 Power Head Seals.png
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Richard A. White
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Re: 55 RDE-17, 25 hp, Power Head O-rings, etc

Postby Richard A. White » Sun Jul 08, 2018 7:48 am

I will have to attach a photo from my phone since it will be easier than trying to send the photo to my computer...yad yada yada...gimme a sec, I will also send you a PM.

These things are awesome motors and if you have the ability to go thru the whole motor, you wont regret it, your wallet might look at ya funny but it is worth it...

20170627_180519.jpg
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FrankR
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Re: 55 RDE-17, 25 hp, Power Head O-rings, etc

Postby FrankR » Sun Jul 08, 2018 7:57 am

The o-rings you speak of----The upper one and one of the lower ones are inside the carbon seal. No need to pull the powerhead to access the upper one. But of course the powerhead does have to come off if you want to access the lower one. The second one on the lower end is around the bearing, and the powerhead has to not only come off, but also come apart to get at that one----not a normal service requirement.

You know those lower pans can be removed without removing the powerhead---don't you?

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Re: 55 RDE-17, 25 hp, Power Head O-rings, etc

Postby jpatti75 » Sun Jul 08, 2018 8:01 am

Bucc,

Yes, do change those o-rings...at least the top. I just did it on my Rd-13 and it was an easy job. The hard part was cleaning off all the dried fuel on the magneto. If it is leaking a decent amount of fuel on the magneto, you risk dowsing your points and killing the spark. The compression numbers are low, but that wouldn’t concern me too much until you give it a good run. If it has been sitting a while, the rings could be sticking a bit. Put some Marvel Myster Oil (recommended by Lloyd Lautner) in your tank,it does a good job cleaning out the internals.

As for cheap rattle can paint, I haven’t seen a close match for ‘55 Sea Horse Green. If you’re willing to spend $20, you can get a perfect match here:
http://effena-co-llc5.mybigcommerce.com/paint-johnson/
(Keep in mind your paint is faded, so it may still look different)

JP
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Re: 55 RDE-17, 25 hp, Power Head O-rings, etc

Postby Buccaneer » Sun Jul 08, 2018 8:22 am

Frank, you should never assume I know anything :)
I did not know the pan could be dropped without
pulling the power head, but I know now!
seems that the 10th edition manual is lacking.
To pull the power head it just says pull all the bolts necessary. :(
Someone mentioned in another thread that some of these
o-rings were replaced with "square" o-rings on some models,
and only on the top side and not the bottom side, or visa-versa.
What's up with square o-rings.
I looked at some on McMasters Carr, and it mentioned they are
used in "static" installations, so not sure why they'd be better
for Johnsons?
Thanks!

FrankR wrote:The o-rings you speak of----The upper one and one of the lower ones are inside the carbon seal. No need to pull the powerhead to access the upper one. But of course the powerhead does have to come off if you want to access the lower one. The second one on the lower end is around the bearing, and the powerhead has to not only come off, but also come apart to get at that one----not a normal service requirement.

You know those lower pans can be removed without removing the powerhead---don't you?

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Re: 55 RDE-17, 25 hp, Power Head O-rings, etc

Postby Buccaneer » Sun Jul 08, 2018 8:30 am

JP, Someone had installed newer coils, points, and condensers. It has
pretty blue coils. Not sure what vintage they are. Will have to dig around
for that photo of the coil display.
Both set of points were a little pitted on the "moving" side of the points.
The condensers both tested at .26 mfd's. Perhaps that's the cause?
I've noticed high readings before on brand new Sierra condensers.
Anyway, I replaced with new .20 caps from Digi-Key.
No oil on my mag plate now.
Regarding the paint, when I looked last night at FN/A paint, perhaps
via EBay, it was $21.95 for a can, but then $9.95 for shipping.
Wonder if they'll be at Tomahawk this year?
Thanks!


jpatti75 wrote:Bucc,

Yes, do change those o-rings...at least the top. I just did it on my Rd-13 and it was an easy job. The hard part was cleaning off all the dried fuel on the magneto. If it is leaking a decent amount of fuel on the magneto, you risk dowsing your points and killing the spark. The compression numbers are low, but that wouldn’t concern me too much until you give it a good run. If it has been sitting a while, the rings could be sticking a bit. Put some Marvel Myster Oil (recommended by Lloyd Lautner) in your tank,it does a good job cleaning out the internals.

As for cheap rattle can paint, I haven’t seen a close match for ‘55 Sea Horse Green. If you’re willing to spend $20, you can get a perfect match here:
http://effena-co-llc5.mybigcommerce.com/paint-johnson/
(Keep in mind your paint is faded, so it may still look different)

JP
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Re: 55 RDE-17, 25 hp, Power Head O-rings, etc

Postby Richard A. White » Sun Jul 08, 2018 8:45 am

Might I suggest, that you contact Barry and see if he is going as I am pretty sure he would bring your order to you..

The blues are from the early 70's I think here is the photo:


coildisplay-fullsize.jpg
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FrankR
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Re: 55 RDE-17, 25 hp, Power Head O-rings, etc

Postby FrankR » Sun Jul 08, 2018 9:00 am

Omc went to the "square" o-rings a few years after your motor was built. OMC calls it a "quad ring". They are better suited to a sliding shaft than an o-ring. The shaft is able to move up and down within the bearings, and the carbon seal must slide on it in order to stay in contact with the bearing.

Quad rings.gif
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Last edited by FrankR on Sun Jul 08, 2018 9:03 am, edited 1 time in total.

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Re: 55 RDE-17, 25 hp, Power Head O-rings, etc

Postby FrankR » Sun Jul 08, 2018 9:02 am

Hats off to you for that beautiful job of cleaning the magneto.

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Re: 55 RDE-17, 25 hp, Power Head O-rings, etc

Postby Buccaneer » Sun Jul 08, 2018 11:49 am

That's the photo of the coils I was thinking about. I suppose it's
possible my coils are that old, but I don't believe the condensers
and points were. At any rate, I tested the mag on the Stevens this
morning, and I think it's "good to go".
Thanks.

Richard A. White wrote:Might I suggest, that you contact Barry and see if he is going as I am pretty sure he would bring your order to you..

The blues are from the early 70's I think here is the photo:


[attachment=0


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