OB lower unit gasket material?

[forestcreature]

does anybody know what material the submerged lower unit gasket (behind the prop) on an outboard could, or might be made of?

the old gasket looks and tears like the gasket paper that i would be used to on lubber engines

it is not pressurised, one side has gearbox oil to contend with, the other has water. gasket paper is water and oil resistant. could it just be standard gasket paper?

EDIT: for that matter, any idea what is a good seal material for lower unit gearbox oil drain/fill screws?

 

[sailorman]

It it keeps oil in it will keep water out
you could always use "instant gasket" silicone

 

[VicS]

does anybody know what material the submerged lower unit gasket (behind the prop) on an outboard could, or might be made of?

the old gasket looks and tears like the gasket paper that i would be used to on lubber engines

it is not pressurised, one side has gearbox oil to contend with, the other has water. gasket paper is water and oil resistant. could it just be standard gasket paper?

EDIT: for that matter, any idea what is a good seal material for lower unit gearbox oil drain/fill screws?

I cannot think of any reason why ordinary gasket paper would not be used. The manual for the engine might suggest a gasket t cement or jointing compound as well. Blue Hylomar would probably be a good choice if nothing else is specified.

Can you not obtain a gasket as a spare part ?

Many, if not most, have an O ring in that position. But if yours has a gasket then it has a gasket !

The gearbox drain and level screws usually have a hard plastic (Nylon ?) washer or an O ring. The design of the screw would reflect which

What make, model and year of outboard are we talking about anyway. If its not too ancient and one of the mainstream makes spares may well be available. Possibly even an online workshop manual.

 

[forestcreature]

thank you both! i think that seals it. chortle ahahaha

it is a Mariner 2hp 2 stroke that somehow ended up in my garage, and it is in really good condition. i think all it really needed was a fuel system cleanup, but i wanted to give it a checkup anyway. wish i hadn't bothered!

Can you not obtain a gasket as a spare part ?

i can, i just want to be cheap and independent. btw i mean the casing gasket, not the propshaft seal. anyway thank you, great confidence-building answers

 

[VicS]

thank you both! i think that seals it. chortle ahahaha

it is a Mariner 2hp 2 stroke that somehow ended up in my garage, and it is in really good condition. i think all it really needed was a fuel system cleanup, but i wanted to give it a checkup anyway. wish i hadn't bothered!



i can, i just want to be cheap and independent. btw i mean the casing gasket, not the prop shaft seal. anyway thank you, great confidence-building answers

Depending on age the gasket may no longer be available anyway! Late models appear to have an O ring rather than a gasket but that's not available either!

One thing to consider if fettling up an outboard of unknown history is changing the water pump impeller.


You might find a service manual that covers it at http://boatinfo.no/lib/library.html

 

[forestcreature]

thank you!

i think i have the right service manual from boats.net (Yamaha '84). wow boatinfo.no is trippy though

an impeller swap is part of the plan. is there any standardisation there, i.e. for a given shaft diameter and chamber diameter? i'll get the pump service kit for that anyway, if i can