1955 Evinrude 25hp Gear Case Seals

[Old Elgin]

Hello. I thought I had finished making my Evinrude 25hp Big Twin a relaible motor when I noticed that I had to replace the gear set and clutch dog on its first lake test. I ordered a brand new gear set and clutch dog, took off the lower gear case, and got every thing back together in the lower gear case. When I went to mount the case with gears to the lower unit, I noticed water was coming out of the lower unit when I tilted the motor back to install the gear case. I didn't have an oil leakage problem before as the oil was water free. Is it normal for water that collected up by the water pump or exhaust to pour down once I released the lower shift rod or or did I create a problem that needs to be fixed. I feel that I'm almost done with this motor and want to make sure its right before I put the gear case back on. Thanks a lot for your help!

 

[Mas]

Re: 1955 Evinrude 25hp Gear Case Seals

If you've got water inside the case where the gears are, you've got problems...I'm I reading you correctly?? Water every other place in the exhaust leg and around the water pump is normal. Tilting the motor will usually free water. Is the drain plugged? I had to re-drill a plugged passage in my '57 35HP Lark. You may want to check this out.

Mas

 

[Mas]

Re: 1955 Evinrude 25hp Gear Case Seals

Here's another pic:

 

[Mas]

Re: 1955 Evinrude 25hp Gear Case Seals

Here is another pic:

 

[Old Elgin]

Re: 1955 Evinrude 25hp Gear Case Seals

Thanks for the great info. Is there a gasket that seals the shift rod and the hole it goes through from the water above so that no water gets into the gear case?

 

[F_R]

Re: 1955 Evinrude 25hp Gear Case Seals

There is a shift rod seal, but didn't you say there was no water in the gearcase?

 

[Old Elgin]

Re: 1955 Evinrude 25hp Gear Case Seals

Yes, there is no water in the gearcase, but I can't see the seal because I don't have the lower unit removed, just the gear case. I think I understand now. Water was up near the exhaust/pump area. I removed the shift rod, and water came in through the hole where the rod was. So now, when I replace the rod, it should seal again and all should be ok?

 

[Mas]

Re: 1955 Evinrude 25hp Gear Case Seals

You should have the LU pressure tested for leaks to make sure. I personally would replace the shift rod o-ring (a tool is needed to remove the o-ring bushing properly) as well as the drive shaft seal, prop seal, prop seal housing o-ring, and of course, the spaghetti seal. If you've got it open, now's the time...not after you have it all put back together. Basically, reseal the case!

If I'm understanding you correctly, you have the skeg (lower half of the gearcase) removed from the gearcase...right??? If the gearcase is not opened, just have the LU pressure tested.

Mas

 

[Old Elgin]

Re: 1955 Evinrude 25hp Gear Case Seals

I removed the gear case and replaced all the gears and clutch dog. Today I removed the rest of the lower unit and checked the water pump (previous owner said it was new) and it looked fine. I also replaced the pinion gear. Now, I just don't see a gasket in the hole where the lower shift rod goes through to the gear case (the "shift rod hole" - referenced in the picture above where you show the hole not to drill through.). It almost seems as if a seal was never there, but yet it wasn't leaking water. I sure want to get this done right because I have already spent so much time on the upper unit (carb, magneto, fuel pump addition, shift lever, cowling...) I must admit that this is a fun motor to work on though!

 

[Mas]

Re: 1955 Evinrude 25hp Gear Case Seals

The o-ring sits in a recess inside the brass bushing. Look toward the shift-rod hole from the gear side, and you should see a brass outline that is flush with the casting. The bushing is best removed with a "shouldered rod" of exact diameter, but there are other ways to get it out.

Mas

 

[Old Elgin]

Re: 1955 Evinrude 25hp Gear Case Seals

I can see it now! Thank you so much for the information. It great to know there are people that still enjoy working on old motors and and being so kind in sharing their knowledge with others.

 

[Old Elgin]

Re: 1955 Evinrude 25hp Gear Case Seals

Just a follow-up...I got everything back together and noticed that oil was leaking out of the prop seal. I took everything back apart and removed all the gaskets, including the shift rod bushing and o-ring (using the spade drill bit and socket extension I saw on this forum!). I wish I had replaced all the gaskets the first time, but I guess I had to learn the hard way and do everything twice! Do you recommend I replace the drive shaft seal on the lower unit and if so, how hard is it to do?