Tecumseh top oil seal install question

[JohnnyCanuck]

Hello everyone,

I posted a long time ago about a Tecumseh VLV-126 with an oil leak that I thought was coming from the top end of the crankshaft. I finally had the time to work on this engine after many years and managed to get the flywheel off.

The oil leak is indeed coming from the top end oil seal. I managed to get the old oil seal out but I have a question about how to install the new oil seal.

When installed, should the new seal sit flush with the top of the engine, or should I press it in all the way so that it is recessed?

The engine model is a Tecumseh VLV126 502045F.

Thanks in advance for any help!

 

[sgkent]

are there witness marks you can use to see how the last seal was installed? Also be sure to make sure the breather is working and not clogged. Many a good seal will leak oil if the crankcase pressure is high due to a clogged breather.

 

[JohnnyCanuck]

Thank you for the reply!

The old seal was sitting flush with the top of the engine, but I am not sure if that is what was causing the leak. I want to be sure I install the new seal correctly so I don't block any oil feed holes for the crankshaft upper end.

I am not sure how to check the breather. On this engine, there is a tube that connects from the top of the engine to the carburettor. I think it sends the oil mist back into the engine to burn it off for emissions control.

Is there some other breather I should check?

 

[sgkent]

I don't know your engine but make sure any breathers are open and connected. If there is a drain back hole, and it is in the seal flange area, measure how deep it is and don't block it. If there is no drain back hole put the seal back as it was. Inspect the crankshaft for a wear groove. If there is one try to put the seal in so it rides above or below it. If the seal protrudes it may hit something above it. If the crank is a but rusty or pitted, carefully polish the area the seal will ride on. One possibility when any seal like that fails is that as the crankshaft turns it wears the bearing. When a seal is new it is pliable and can adapt to any wobble, but as it hardens it loses that ability. Good luck with it.

 

[bertsmobile1]

No seals leak out of the centre wher the shaft rotates
The shaft will have a wear ring in the place that the seal ran on it
It is good practice to put the new seal in just far enough to be just lower than this ring
Note the lip nees to be just lower, not the whole seal the idea is the new seal LIP is running on clean metal
Usually there is either a drain hole or supply hole in the housing that can be blocked off if the seal is pressed in too far
So I would look at pressing it in about 0.020" lower than flush if theold one was flush.
If you have the old oil seal it will help if you cut in in hals so you can clearly see when the old lip actually was .
Note most modern seals are double lipped the most external one is not oil tight and is a dust seal to protect the oil lip .

 

[JohnnyCanuck]

Thanks for all the replies. The old seal (and the new one) are made of a kind of hard rubber. They are flexible and can be pushed in by hand (if a little oil is used on the engine). I didn’t see any wear marks when I removed the old seal. I will check again as I need to replace the flywheel and am waiting for it to arrive. The parts for this engine are difficult to find now that Tecumseh is no longer in business. The crank was in pristine condition. No rust whatsoever as the seat for the mower sits directly on top of the flywheel. I have winterized the machine every year that I have had it and kept it in dry conditions. It’s been well maintained.

All the breathers are open and connected. I have the service manual but it only addresses the bottom-end seal and not the top end. I’ve tried looking online for a picture of a VLV126 with the flywheel removed, but no luck.

The service manual is here: https://www.smallenginesuppliers.co...h_VLV-4-Cycle_Engines_Service_Information.pdf

Bottom seal replacement is on 12-2.

What I wouldn’t give for a photo of a VLV126 with flywheel removed!!

 

[JohnnyCanuck]

Knocked the flywheel off, replaced top seal. Seated it so it was level with the top of the engine. There was a kind of witness mark on the shaft that suggested it should be seated flush with the top of the engine. Reassembled everything and ran it for 30 minutes under load, at idle, etc…. It’s DRY, NO LEAKS! I think this has fixed it.

Thanks for all the help! The flywheel came off rather easily. I used a pry bar and knocked the flywheel off. Took 3 hits.