1957 Johnson QD-18 Lower Crankcase Seal

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aquasonic
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Location: Narragansett, Rhode Island

1957 Johnson QD-18 Lower Crankcase Seal

Postby aquasonic » Thu Oct 12, 2017 5:05 pm

I am servicing a QD-18, and currently have the powerhead removed. Looking at the lower crankcase seal assembly, I can see a circular clip around the crankshaft. That circular clip holds in an expansion spring. On the parts diagram, it appears that behind the spring, there is a seal and two O-rings of different diameters.

While I have this powerhead off, I would like to replace any parts such as O-rings that always seem to need replacement. Can the seal and o-rings be accessed by removing the circular clip, or are they inside of the crankcase?

Thanks for any advice.

Chris_P
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Re: 1957 Johnson QD-18 Lower Crankcase Seal

Postby Chris_P » Thu Oct 12, 2017 6:13 pm

You can replace the important one.

Take out the circlip. Slide the spring assemble out. It will have 2 plates, one on either side. Then you slide out the black carbon seal. They are more fragile than they look. Don't be surprised if it breaks, that happens. Inside of that, you will find an o ring. Change that while you have the powerhead off. The larger o ring sits around the lower bearing, and you cannot get to that without opening up the powerhead.

By the way, pay attention to the order you take things apart. Especially the carbon seal. It goes in one direction only.

aquasonic
Posts: 275
Joined: Tue Mar 10, 2015 7:13 pm
Location: Narragansett, Rhode Island

Re: 1957 Johnson QD-18 Lower Crankcase Seal

Postby aquasonic » Thu Oct 12, 2017 6:23 pm

Good advice for sure. Once again, thanks Chris.

Bill McNamara
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Location: Ontario Canada

Re: 1957 Johnson QD-18 Lower Crankcase Seal

Postby Bill McNamara » Fri Oct 13, 2017 8:43 am

Just curious......what were the symptoms leading to the change?

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Buccaneer
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Joined: Mon Mar 09, 2015 9:34 pm

Re: 1957 Johnson QD-18 Lower Crankcase Seal

Postby Buccaneer » Fri Oct 13, 2017 5:00 pm

Bill, Symptoms of the "change" can be irritability, and hot flashes.

Bill McNamara
Posts: 174
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Location: Ontario Canada

Re: 1957 Johnson QD-18 Lower Crankcase Seal

Postby Bill McNamara » Sat Oct 14, 2017 8:42 am

Buc..... ha ha, been there, seen that happen.


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