Copper crush washers ok to use?

[Rob406]

Would certainly save me a lot of time and effort if i could use nylon. Could anyone confirm / deny?

 

[Vic.S]

Would certainly save me a lot of time and effort if i could use nylon. Could anyone confirm / deny?

As already said Nylon is hygroscopic. It does absorb water and swells slightly. I thought that was well known but it is not going to be a problem with the gearcase oil screws. Acetal ( Delrin ) is used where this swelling is a problem. eg for bearings . It also has superior mechanical properties. It is possible that the washers are in fact acetal but I don't know.

There are two types of oil screws . Those where the heads have a flat underside for a flat washer and those that have a recess for an O ring. If you fit one of the flat washers to a screw intended for an O ring it will stand slightly proud rather than be flush with the outside of the gear case. It may not seal so well either.
There are also slotted and Allen socket head versions.

The parts list shows the type with a washer in both locations for your engine although it also shows a magnetic version for the drain screw.

I would change the vent screw for one that accepts the ubiquitous flat washers. You can find the parts numbers in the parts lists on this site

( FWIW I have never changed the washers in my Evinrude. One always stays in the hole the other stays stuck on the screw. I do not disturb either. i carefully refit each screw in the position it came from. Just saying , not recommending)

 

[racerone]

A lot of overthinking on this simple topic.

 

[Rob406]

As already said Nylon is hygroscopic. It does absorb water and swells slightly. I thought that was well known but it is not going to be a problem with the gearcase oil screws.

I am sorry. But is nylon ok to use or no?

Not trying to over complicate. Just want peace of mind. I like changing oil often.

 

[tphoyt]

Personally I would have no problem with using nylon.

 

[dingbat]

Seems people are confusing hygroscopic (absorbent) and permeable (allows fluids to pass through)

Nylon is hygroscopic but not permeable.

Nylon is saturated ~10% which causes the material to expand roughly 3 to 3.5%.
In other words, a 0.090" thick nylon washer will grow in thickness by roughly 0.003", the thickness of a human hair. Hardly a problem

 

[racerone]

A lot of good gear oil gets thrown out.----No need to change it often if seals are keeping the water out.----If water is getting in you need a complete seal kit !!

 

[airshot]

Most every dealer, BassPro, Cabela's etc stocks those factory fiber washers, I buy them by the dozen so I have them on hand. As far as the screws go, I use what is called a " low head" hex head cap screw to replace drain screws if the dealer doesn't have replacements. They have a large head with a flat underside for a washer. In some cases the head dia was a little large so I chucked it up in a drill and spun it on a belt sander to the correct size. Quick, simple, easy and cheap and it works perfectly. Have used the nylon/ fiber washers in a pinch with no issues. If they were to absorb any water it would be so minut it would not matter. Little things like these , I try to keep a couple spares on hand, well worth the few bucks they cost..and saves chasing them down when you really need them !!

 

[Faztbullet]

Use the Merc yellow washers as they are reusable,dont deform and I use them on all my customers with no leaks.

 

[Rob406]

Thanks guys. Went with the nylon. Available at ace hardware. All is well.