Topic: 57 Johnson 10 HP QD18 Gearcase repair – Antique Outboard Motor Club,Inc

This topic has 7 replies, 5 voices, and was last updated 4 months ago by frankr.

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July 22, 2024 at 8:32 pm #289362
Dave
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US Member
I am repairing the gearcase for this Johnson 10 hp. I finally got all the parts but the bearing seal that fits in the end of the prop shaft / gearcase head doesn’t seem like its going to fit. The gearcase head bearing seal assembly is part # 376754. The bearing seal is part # 302495. Just eyeballing it the seal looks to0 large. When I put calipers to it the seal OD is 1.25 in, and the bearing inset for the seal is 1.12 in.

I checked the parts numbers for the 1957 QD18, and they are correct for the seal for this motor. I don’t know that I can get it to fit, even with heating the housing and cooling the seal. I don’t know if trying to see if a machine shop can press it in would help.

Any tips or experience with this would be greatly appreciated.

Thanks

Dave

'57 Johnson QD18 10hp
'53 Sea King 3hp
July 22, 2024 at 9:04 pm #289363
Gary H.
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US Member
First, match it up to the old seal to check dimensions. Maybe it was boxed wrong. Hopefully you still have old parts.

You can also look at manufacturer and part number on old seal and cross reference if needed and also check manufacturer and part number on new seal. Maybe your gear case was changed at some point to a different year that fits but requires different size seals. Just a thought of what might be wrong if anything.
July 22, 2024 at 9:17 pm #289365
mike n
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US Member
i’m not sure i’m on the right track here but if you look at vintageoutboards.com gearcase seal kit 22-30002, it lists the prop shaft seal od at 1.125. it lists it as a 1953 qd14 kit but its worth looking in to. hope this helps.also check kit 22-30001 .it gives a serial number range and a part number for a prop shaft seal 1.125. that may be what you need?

mn
July 22, 2024 at 9:38 pm #289366
Steve D
Participant
My guess is the previous owner either swapped the whole gear case with one from a 1958 or later 18 HP because it’s an even swap except the prop shaft bearing head has the smaller I.D. like you found. Or just swapped out the head because the original was scored, but swapped it with the ’58 and later version. Or it could be as Mike mentions with the serial numbers. The parts page shows a mid year change for the seal. See #35

The larger seal is 302495, the smaller one is 302545 > 313284. Ebay has a bunch of them for $12-$15.
July 22, 2024 at 9:58 pm #289370
Dave
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US Member
Ok, thanks for the info. I destroyed the old seal when I took it out so no luck on the number there. But the OD on that other seal seems correct, I will have to mic the prop shaft to see if the ID will work.

Thanks Guys!!

'57 Johnson QD18 10hp
'53 Sea King 3hp

1 user thanked author for this post.

Steve Martin
July 22, 2024 at 10:50 pm #289379
Dave
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US Member
Nope, I destroyed the old one taking it out.

'57 Johnson QD18 10hp
'53 Sea King 3hp
July 23, 2024 at 10:49 am #289386
Dave
Participant
US Member
Well, Using the seal from the ’58 FD12 18hp is the correct size so that solves my problem. It does make me pause and say to my self- “Self, write down any number you see on parts before you remove them and wreck ’em so you know what to replace them with!”.

Thanks again for all the input! It sure is nice to put a problem on the Forum and get answers back so quickly.

Dave.

'57 Johnson QD18 10hp
'53 Sea King 3hp
July 24, 2024 at 8:16 am #289406
frankr
Participant
US Member
This subject comes up often. Just remember that the older motors used a larger O,D, seal which was later changed to the smaller one (because the metal surrounding the larger seal was so thin that it would stretch/expand and make the seal to be a loose fit). The whole gearcase head & seal assembly from the newer ones will fit and replace the older ones.

1 user thanked author for this post.

Dave
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