Had a look at a Lift motor that took water in last week. The shaft seal on the motor is a radial seal, one lip. It is not a classic seal, David told me it is custom made. I have seen some Parker seal similar to this. They were made from PTFE filled with graphite with the o-ring. If I remember correctly they are made for high shaft speed application to prevent wear on shaft. The o-ring prevent the seal to rotate in the bore.
On the Lift there is also the exact same seal fitted in the prop guard and an o’ring between the matting surface of the motor and prop guard.
If you remove the prop guard you will increase drasticly the chance of water intrusion. The tail cone Lift sell has the same seal. Any custom designed tail cone should integrate a radial seal otherwise you only rely on a single lip seal to do the job.
Managed to save this motor before it was too late, lucky…