1952 Johnson TN28 upper seal question

[j.tsokatos@hughes.net]

I'm restoring this old motor. Disassembled lower unit to inspect water pump impeller and found it to be nearly new. However the upper seal is confusing. I found this illustration (below) and it represents each of the components I found on my drive shaft, except for the pressed on collar 1.25" down from the top the splines.

Here's the problem. The diameter of the spring, shown in the illustration, will easily slip past the aforementioned pressed on collar - not shown. When I disassembled the lower unit the plastic disc, o-ring and brass washer came out on the shaft, but the spring remained in the housing, just below the crank shaft, and I had to pick it out. By me how they got past the spring?

Either the illustration is incomplete/wrong, or am I missing something? I would appreciate any help in solving my problem.

Thanks,

John

 

[Joe Reeves]

Looks like this site auto starred out your site John. Get the graphic on your computer, then you can upload it via the icon left of the "A".

 

[j.tsokatos@hughes.net]

This is the illustration. For some reason I can no longer edit my original post. Thanks for the help.

 

[Joe Reeves]

In looking thru one of my old parts books... a TN-27 model, there appears to be a small hole drilled thru the top portion of the driveshaft, I assume under the splines (hard to tell exactly). This would be similar to many small hp models that followed years later.

The hole would be for a pin to go thru, extending out both sides to retain a washer for the spring to sit upon. However, in the TN-27 parts book, I do not see any graphic mention of said pin, nor a part number... strange.

This would be similar to say a driveshaft to crankshaft seal arrangement of a 1966 5hp or a 1970 6hp Evinrude/Johnson just to mention a few. Look it up.

 

[F_R]

There was a design change in the TN seal and a kit to modify existing motors. i don't have time to look it up right now, but if you sit tight awhile I'll get back with you.

 

[j.tsokatos@hughes.net]

There was a design change in the TN seal and a kit to modify existing motors. i don't have time to look it up right now, but if you sit tight awhile I'll get back with you.

F_R thanks so much for the reply. I think you're referring to the "Seal Assembly Kit - Upper Drive Shaft Casing" and the original part number is 376311. Here's the illustration:

My TN28 definitely does not match the illustration on the right. However, my drive shaft does have the pressed on collar #303031, but it's only down 1.25" from the top of the shaft splines and not the 2 5/8" as depicted in the illustration (right) above.

I can only assume my TN28 is an early original and precedes the updated seal assembly. I will say that upgraded seal assembly make more sense and would make reassembly much easier.

So far I haven't located the kit (376311) or the individual parts to perform the modification

I really want to save this old timer, because it's complete and shows very little use. Paint is faded and the decals are severely flaking off, but it's all there except for rubber on the tiller.

 

[F_R]

Still looking for the instruction sheet but this should get you going.

 

[F_R]

The rest of the story

 

[j.tsokatos@hughes.net]

Still looking for the instruction sheet but this should get you going.

I've got the instructions, but my TN is earlier.

 

[j.tsokatos@hughes.net]

In looking thru one of my old parts books... a TN-27 model, there appears to be a small hole drilled thru the top portion of the driveshaft, I assume under the splines (hard to tell exactly). This would be similar to many small hp models that followed years later.

The hole would be for a pin to go thru, extending out both sides to retain a washer for the spring to sit upon. However, in the TN-27 parts book, I do not see any graphic mention of said pin, nor a part number... strange.

This would be similar to say a driveshaft to crankshaft seal arrangement of a 1966 5hp or a 1970 6hp Evinrude/Johnson just to mention a few. Look it up.

Joe - I really appreciate the reply. There isn't a hole drilled anywhere through my drive shaft. However, my driveshaft does have the pressed on collar that's depicted in the "Seal Assembly Kit" part number 376311.

I do note that for the TN27 kit it does require a drilled hole and a pin to retain the washer, spring and components above.

 

[j.tsokatos@hughes.net]

I've decided to add a bronze thrust washer between the collar pressed on the drive shaft and the base of the spring. This will prevent the spring from slipping past the collar.


For some reason they don't show the collar that's 1.25" down from the tip of the drive shaft. I'll reuse the plastic disk, but I've replace the o-ring since the original one was brittle. The original top washer can also be used.

Once I get it reassemble I'll post and update. I already know it's going to be tricky.