Sealing the early LU Screws

samo_ott

samo_ott

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It's easy to do on the later models as all one has to do is buy the proper soft washer. But what do folks do on the earlier models? I was changing the LU oil on my 4434 (1950 7.5hp Evinrude) today for the first time and see that all they have is a fine threaded screw to fill the oil. No washer, no seat. And as my LU was full of water (surprised it still worked) I'm wondering if folks use sealant on the screw or what? And what type of sealant if so? thx.
 
Scaaty

Scaaty

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Re: Sealing the early LU Screws

samo_ott said:
It's easy to do on the later models as all one has to do is buy the proper soft washer. But what do folks do on the earlier models? I was changing the LU oil on my 4434 (1950 7.5hp Evinrude) today for the first time and see that all they have is a fine threaded screw to fill the oil. No washer, no seat. And as my LU was full of water (surprised it still worked) I'm wondering if folks use sealant on the screw or what? And what type of sealant if so? thx.
Click to expand...
If its just a tiny screw..(no drain..just a fill screw that ya fill by laying on its side), just make a cork gasket for it, little blue Sillycone. Sure no fill/drain screws? (probably a dumb question).
FR shoulld pick up here soon..he knows them old Rudes..
I'd just do a full "cheap" rebuild of all seals and pump parts. Laingsoutboards has all ya need..(just got the seals/pump gaskets from Jeff today for a rebuild on my old CD 18 5.5...) best to do the whole L/U, and then good for a few more decades..
 
Chinewalker

Chinewalker

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Re: Sealing the early LU Screws

Scaaty - there isn't even a shoulder on the screw in the units Samo is referring to. I beleive they are something akin to NPT (Pipe Thread). Might try some plumbers tape or some really goopy sealant...

- Scott
 
wbeaton

wbeaton

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Re: Sealing the early LU Screws

I think I'd try teflon tape. I haven't had one of those lowers apart, but I doubt you can buy many or any of the seals. You may have to make most of them.
 
F

F_R

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Re: Sealing the early LU Screws

Those are tapered pipe threads on those screws. They seal just by screwing them in, because of the taper. However, you can help the sealing by using some gasket sealant or teflon tape on them. Just make sure you don't use anything that will set up hard and make them hard to get back out.
 
S

seahorse5

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Re: Sealing the early LU Screws

Check the proper manual about your 1950's engine's gear lube.

Back then, many of the motors used a #105 marine grease, not an oil like they do today.
 
C

CharlieB

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Re: Sealing the early LU Screws

Av-Perm, Mercury Perfect Seal, Teflon Paste

All are NON-hardening

Some J/E manuals even call for it to be used in the LU attachment bolts to the mid, to ensure against seizing, keeps water out of the threads and is a very good improvement over anti-seize ( in that particular application/location)
 
samo_ott

samo_ott

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Re: Sealing the early LU Screws

The '53 manual says to use GX - 90. and if you dont have any to use SAE 30! So you can use the same oil in the gas and the LU. Funny. But it does say to replace it with 90 weight when you can if you do use SAE 30. It also says to drain vertical and to fill on it's side...

Thanks all for the comments and I agree with Wayne, I dont know if I want to take the LU apart as I doubt I will find the seals for it... It's a lot cheaper to change the oil a lot and maybe go to synthetic as it will work better when 'waterlogged'.

And I also agree with Scott, it looks like it might be NPT.

Good thing I got another engine for parts this year!

Steve
 
Scaaty

Scaaty

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Re: Sealing the early LU Screws

OK, its an NPT plug then...little Teflon tape should do it..just snug her up..
 
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