[PSUBS-MAILIST] Seals again

[s_lindblom@conknet.com (Steve Lindblom)]

I just ran into a friend who has a Dacor DPV scooter, and he'd just
replaced the seals, and still had the old one, which he gave me. I was
suprised to see that it was just a plain old rubber lip seal, the kind with
a little spring inside to hold tension on the shaft, as used for the rear
oil seal on a car engine. He got replacements at the local bearing supply
shop for a couple dollars each (it uses two in series).

Dacor says the scooter is good down to 160', and I think the unofficial
word is that they are good down over 200'.

What I found surprising is that these are just about the simplest seals
imaginable, and I'd always assumed they wouldn't be up to this application
given the fact that they are running in water not oil, and are exposed to a
fair amount of pressure. But there are a heck of a lot of Dacor and Apollo
scooters out there, and seal problems don't seem to be common.

The other neat thing is it is almost a direct fit into the little 30lb Minn
Kota flea market motor I've been using as a test bed - there's even room
for two of them, above the standard seals. I say almost because the hole
around the prop shaft on mine is a little corroded, and I don't know what
it originally measured. I may have to clean it up a bit and sleeve it, or
maybe just some Loctite Sleeve Loc will do the job. Probably worth
mentioning that the seals should be installed "backward" in this
application, that is to say, with the open/spring side facing out so the
pressure tightens the seal.

So we got the Dacor using $3 seals for 200', and the Scubapro "Salad
Shooter" with a Minn Kota motor (the entire module, skeg and all, slung
down below the battery housing and disguised with a plastic shroud) merrily
cruising at 180'. Gentlemen, is pressure compensation really necessary?