LU Drain Seals-1990 15 Hp Evinrude

[OptsyEagle]

So I bought this motor at the beginning of this season and want to replace the lower unit oil to prepare for next year. When I drained the oil, by removing the drain screws, I noticed that they did not have any washers on the drain screws or left in the screw hole. In the picture on the right you will see the drain screw from the 1990 15Hp motor. The screw on the left is from a 1975 9.9 Evinrude that I always put on a new nylon washer before tightening them onto the LU of the motor.

The oil I removed from the 1990 model did not have any water inside it, so it must have sealed up the LU properly. You can see from the picture that the thickness of the outer base seems to take up the dimension of a nylon washer and there seems to be a cone amount to it that must seal up the LU properly to not allow water into it. That cone material is black whereas the rest of the screw is metallic and maybe it is a rubber seal inset into the screw. I don't want to poke at it to hard in case it is rubber and damage it.

When I review the parts list for my model they seem to show a nylon washer or at least a washer of some type. Does anyone know whether this model or this screw requires a nylon washer or not or how this particular screw design works.

 

[Crosbyman]

sometimes.... the darkenned...crushed washers are stuck in place and you need a small pick to pull them out look VERY closely

in any event inslall new ones everytime to change the oil

 

[Vic.S]

I think your 1990 15hp may have drain/ level screws which should have O ring seals. Are you sure there are not O rings still on the screws?

If I am right you have a choice
New O rings part # 0333572

Or new screws c/w washers # 0307551
and subsequently new washers ( like your 9.9 ) # 0311598

But don't fit washers on the screws designed for O rings

(Please check the above part numbers)

 

[racerone]

Correct , they likely installed new screws that use 0-rings.----I prefer the nylon washers myself.

 

[OptsyEagle]

Yeah. It is probably an O-ring inside the screw. If I used the nylon type gasket it would leave the screw offset and not flat with the motor on the outside. The parts list talks about screws with gaskets and also talks about O-rings as well. I suspect this type of screw I have on this motor requires an O-ring. I will get some new ones before I poke at it.

Thanks for the replies.