What did I do to my old Johnson!?!?

[gjonz]

I guess I got carried away today.

I thought I'd go out and put the new head gasket and head back on my RD-18. Somehow, I ended up noticing a few things that looked suspicious, and ended up tearing the whole thing down to...well...zip lock bags full of parts sitting in boxes now.

All this started because the flywheel nut was crossthreaded and a neighbor chased the thread so I could still use it. After all only the starting thread was knarled.

I found that after removing the powerhead that there was NO seal. The retainer clip, spring, retaining washers and rubber seal are gone.

Glad I went nuts and really gave this thing the once over!?!?

Also my cam for the points is cracked! Where do I find that?

I pulled the crank and pistons and found the lower piston had some minor scoring on the side in one spot. The other looked fine and the cylinders have very shallow scoring in the same identical spot as my 30HP Javelin. Nopt sure I should worry about it though since it seems very minor. Should I replace this piston since I've got it out. Should I replace all the rings? Anything else?

I want to replace both top and bottom seals as long as I'm at it too. Anyone know the part numbers and availability.

The bearings and everything else look great.

Is there anything else I should do while putting this thing back together. Any trick I should know about?

Sorry to ask so much, but our local dealers are not very helpfule, and don't want to "waste their time on projects motors". Harumph.

Thanks gang! This is a great forum...and I'm grateful to you all for your knowledge.:redface:

Greg

 

[1946Zephyr]

Re: What did I do to my old Johnson!?!?

Yea, I would recemend replacing the pistons, if they're scored. You could try Seaway Marine, or Engine Blade and Prop. There may possibly be some AOMCI members here who would be willing to help you out on that too. Some of these guys have plenty of this stuff laying around collecting dust.

How do the cylinders look? If the cylinders are in good shape, then you'll only need to hone them out. These notors held up real good and I am yet to see one that has a taper in the walls.

I may have a cam for your points, if you can give me a measurement. I happen to have a few left here and one that may fit yours.

I sold off my collection a few years back, but I do have a couple little pieces left that I never threw out.

 

[F_R]

Re: What did I do to my old Johnson!?!?

from the top:
302538 Carbon seal
302540 o-ring replaced by 305098 quad ring...inside carbon seal
303801 washer
302537 spring
302594 washer
302536 retainer

Con rod bolts torque: 180-186 in/lb if they are 1/4-28. 216-222 in/lb if they are 9/32-28.

 

[gjonz]

Re: What did I do to my old Johnson!?!?

As for the cam, I will measure it tomorrow.

Thanks for the part numbers. Are these readily available, or do I need to look for them at the scrap yard?

Thanks again!

Greg

 

[F_R]

Re: What did I do to my old Johnson!?!?

I just checked. The 302539 is no longer available. Everything else is. www.sea-way.com probably has it all. The cam is 510169. It's pricey. Better check around.

Those cams are sometimes broken by somebody using an air impact wrench on the flywheel nut which forces the flywheel down the taper and against the cam. When that happens, the flywheel is also shot. I keep preaching you must use a torque wrench and tighten flywheel nuts to spec.