Lower Unit Gearcase Reseal on 1974 Johnson Evinrude 6R-74C

oldevin

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Question: Does the small nicks in the Gearcase Head and Drive Shaft Housing Seal and Assembly require these parts to be replaced?

Please see ATTACHED pictures. I circled the nicks in RED. Apologies, I have not cleaned these parts up with a wire wheel yet.

They are each pretty expensive...$128 and $180 I believe.

I searched this forum pretty extensively but could not find an exact similar case.

In the process of replacing my impeller, I drained the Lower Unit Gearcase of oil and it was really milky (full of water). Therefore I am resealing the Lower Unit Gearcase.

In the process of doing so, I had to remove the Oil Seals off the Gearcase Head (382291 #48 on below page) and Drive Shaft Housing and Seal Assembly (382796 #13 on below webpage):
https://www.marineengine.com/parts/...l=6R74C&manufacturer=Johnson&section=Gearcase

I wish I had realized in the first place, but I had to soak both pieces in PB Blaster for 2 days before I made another attempt with a Lisle Adjustable Seal Puller (5 position). My first attempt without could cause a hernia if not careful (be forewarned!) I am now sold on PB Blaster for sure and will buy a can of that stuff, and it made a huge difference with the seal puller and a small vise.
OldSeals.jpg

GearcaseHeadNicksOnOutside.pngGearcaseHeadNicksOnOutside2.pngDriveShaftHousingAndSealAssemblyNicks.pngDriveShaftHousingAndSealAssemblyTop.png
 

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Joe Reeves

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The gearcase head..... As long as the O Ring seal area is a seal-able area and the brass bushing isn't oblong worn so that the propshaft rotates true.... Personally I'd use it, assuming you intend to install a new seal in it?

The housing and seal assembly that's located under the water pump... all you're interested in is the gasket sealing properly, also the seal which again, I assume you intend to replace. And again, personally, I'd use if the brass bushing is true..

Use "Gasket Sealer" on the gasket, available at any auto parts store... comes in a can with a brush attached to its screw off cap.

Use Bombardier 3M Product #847 which may be listed as Scotch-grip 847, part number 776964 on the "O" Ring.... the Spaghetti Seal on the skeg.... between the impeller housing and the plate,... and between the plate and the housing under the plate
 

oldevin

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Joe Reeves and Crosbyman, thanks much!!! Yes, I will install new seals. I will test out the drive shaft and propeller to make sure they rotate freely, true, and properly in the associated gears, and if there is any akwardness in the rotation - I will reassess at that time. Thanks much again!

Joe Reeves - quick question - when you say:
on the "O" Ring.... the Spaghetti Seal on the skeg

Are you referring solely to the Spaghetti Seal on the skeg? Or is there another O-ring somewhere you might be referring to?

I am looking at the diagram in the attached link which was not properly attached the first time, apologies.

Thanks much!
 
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oldboat1

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....after you get it situated correctly (tend to stretch it when installing, in my experience).
 

Joe Reeves

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Joe Reeves - quick question - when you say: on the "O" Ring.... the Spaghetti Seal on the skeg..... Are you referring solely to the Spaghetti Seal on the skeg? Or is there another O-ring somewhere you might be referring to? !

I'm referring to the "O" Ring (#50) on the gearcase head... and the spaghetti seal (#26) on the skeg as per your attached diagram.
 

oldevin

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Joe and racerone, got it, thanks much!! Will do. Attached is a pic of the Gasket Sealant I found at O'Reilly Auto Parts that fits your description. Oldboat1 that is also a good tip (o-ring below the brass bushing using the Evinrude tool)!!!

One more question. For the gearcase (skeg) screws - they were on pretty tight!! I am assuming they were on with waterproof Loc-tite of some kind...3M 4200 or 5200, perhaps? What would you recommend goes on the threading of those screws? And what solvent should I use to clean off before re-applying?

Also #1, #2, #3, #4, #5, #6 in the diagram, above the Drive Shaft Pin, they seem to be in the upper unit somewhere...is that correct? So hopefully I should not need to reassemble these if I mount the Lower Unit back onto the Upper Unit properly with shift rod, water tube, drive shaft...

Thanks again Gents

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oldboat1

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....after you get it situated correctly (tend to stretch it when installing, in my experience).

wow. lot's of activity!

Just for clarity, I was referring to the spaghetti seal on the skeg.... I have a very old can of OMC gasket sealer -- probably the 847 (or similar) that Joe describes.
 

Joe Reeves

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wow. lot's of activity! Just for clarity, I was referring to the spaghetti seal on the skeg.... I have a very old can of OMC gasket sealer -- probably the 847 (or similar) that Joe describes.

No, the substance I speak of is a very sticky dark colored substance that comes in a fairly large tube. It was originally called "OMC Adhesive" but of course Bombardier had to change that. The sticky quality of it would make getting it out of a can and placed exactly where one would need it impossible.
 

oldboat1

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Yeah, the stuff I still have is about 25 years old, and in a can with a brush. It now has the color and consistency of a Slo-Poke sucker (maybe slightly licked on consistency).
 

oldevin

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Apologies no replies here. My mom went to the hospital emergency room and she is doing ok but its been a rough few days. Getting back on this.

Crosbyman, Thanks alot, that helps! I will make sure to trim the ends just barely over the seal on each side with a tiny bit left. (I think I read somewhere 1/32 of an inch)

What can I use to clean off the gearcase skeg screws? I'm assuming they have Loc Tite Blue or 3m 4200/5200 on them from previous application.

What should I put on the gearcase skeg screws when I reseal the unit? 3M 4200?

In the Johnson Gearcase link below, #1, #2, #3, #4, #5, #6 in the diagram, above the Drive Shaft Pin - these are in the Upper Unit correct? I am assuming when I reconnect the Lower Unit they will all be "up there".
 

oldevin

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Joe, I did find this, might this work? (See attached link with Johnson OMC 508235 Gasket Sealing Compound) I will see if I can find the old stuff you might be speaking of Joe. Thanks much.
 

oldevin

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Attached is a picture if the link is inconvenient - is this the correct stuff and/or will/should it work?
 

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