Prop pinion shaft seal

I am up a bit of a corner,I have a yamaha 5BS aircooled two stroke outboard.I have just given it a complete service and it runs sweet.
What I thought was a gearbox filler plug leak has turned out to be the seal on the crown wheel and gear dog shaft.The oil was at about 1/3 of it's capacity when I stripped it.
Because of the age,it seems like these seals are no longer available.This is the previous model to the type that made it's debut in the USA in the late 70's.
I was thinking of using PTFE plumbers tape on the shaft to make it seal.
There is a shoulder on the shaft that the tape would sit against to keep it in place.
There is not much info on this model to be found,especially the specs.
Anyone got any idea's?

 

Is this a true lip seal ("Simmer ring") or just an O-ring? There probably is a standard product from SKF that fits or can be made to fit.
Another option is to press a thin bushing on the shaft so the old seal gets a second chance. I would not trust Teflon tape on a rotating shaft for more than a few minutes.

 

I suspect he is talking about a screw in the side of the lower unit that looks like an oil drain/fill screw, but actually is a set screw type of thing, that locates a mechanical component in the internals, in some engines. No rotation. I think !

 

Can you post a photo vb

 

Hello again CDK,the seal is the type with a curtain wire type spring in it.
(simmer ring ?)
I can't tell if it's stepped or not,it's behind the bearing,the trouble is,I don't know if the bearing has to come out first to access the seal.I could remove the bearing no probs,but I don't want to damage what's left of the seal if I can't get another one.It's a bit of a catch 22 really.There are letters and numbers on the seal,but they are hard to see,I think maybe a strong light and a magnifying glass might be the answer.If the seal isn't stepped,like you say,I could probably find one of the right ID and OD by SKF.
The dia of the prop shaft is stepped to take the bearing after the prop,and the seal sits on the smaller dia against the shoulder.I was going to put the PTFE tape against the shoulder and squash it against the seal,so in effect,It wouldn't be bushing the seal,but sealing the end.
I think I might have to bite the bullet and strip it.

 

Hi Mr E,it's the shaft that the prop sits on,the seal is to stop the oil leaking out,and the water getting in,it's the main drive prop shaft.

 

Are you talking about the prop shaft seal. I can't make sense out of your last post. You are saying the bearing is on the prop side of the seal. Post a pic so people can help you.

 

Hi Brendan,I don't think a pic would show enough to explain it,even with the shaft with the crown wheel out,the seal is behind the bearing.I was trying to avoid damaging the seal in case I can't get another one.
The reply to CDK explains it.

 

No worries. I have never seen a lip seal that could not be matched at a bearing service. I googled your engine and found a parts diagram. Have a look at that and you will see how it comes apart. Its pretty standard . Remove the prop and rear carrier *** to access seal. The carrier thread is quite often locked up. Run a heat gun or hairdryer over it for a few minutes before you try to unscrew it.

 

Thanks for your interest Brendan,I'll have a google.
I have had the carrier casing off,there were two bolts holding it on.I have a new trick for removing aluminium oxidised bolts,spray them with white vinegar,leave them for an hour,then apply heat to the casing.It worked great when I changed the impellar on my 18hp Evinrude.
Incedentally,the impellar was serviceable,it was the mesh filter in the water pickup near the prop that was completely blocked.

 

Nice one,I googled it.
There are two seals,both the same,part No-93101--13055

Thanks for the info
VB

 

I had not heard the white vinegar tip before. I will file that one for future reference. Thanks.

 

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