1969 Evinrude 18 HP Fastwin Lower/mid unit water drain ports

[Lostuzer]

1969 Evinrude 18 HP Fastwin
18902D - E12329 Converted to Short Shaft

I broke my drive shaft last month and decided while I had the OB in pieces I?d clean, sandblast, and paint. BTW I found this primer and wondered if this is what I should get...

Questions pop up left and right as I delve into this project. One subject pressing me right now concerns the ports I cleaned where the water enters in the lowest places. The ports were sealed shut with what appears to be aluminum oxide and sediment.

I have a question mark on the pics and as best as I can figure the cavity and port meet. I?ve so far removed little the grey/white rock like material from the passageway, from the inside. It will be very slow progression if they do meet.

My questions are:

Is my theory about the ?question mark? passageway correct?
Is it necessary that this passageway be opened?
Would it be OK if I drill the ports to approximately twice the diameter to avoid future clogging?
Where can I find some inexpensive paint close to Evinrude blue that will last?
And any input about the primer.

Thanks one and all,
Bob

 

[jbjennings]

Re: 1969 Evinrude 18 HP Fastwin Lower/mid unit water drain ports

I hope some of the real motor guys check in on your question but I'll try and help a little for now. Most of the holes you've shown are just to drain water out of teh midsection and such so that water doesn't freeze in there and break the housing. You being in Florida, I'm not sure if those holes being perfectly clear are a real problem, since it doesn't freeze hard in Florida as far as I know. I wouldn't drill them twice their size. I'd just clean them out as best you can and don't worry about 'em. I have no experience with that brand of paint. I would recommend that if you use their primer, you'd better use their paint, too. Using different brands of primer and paint is a painting disaster waiting to happen. Make sure you pick a low humidity day to paint the lower unit or it won't stick right. Be sure it's clean and pay special attention to the flash times as well. It's tough to get it to stick to aluminum good enough to stay on.
Good luck,
JBJ

 

[F_R]

Re: 1969 Evinrude 18 HP Fastwin Lower/mid unit water drain ports

Well, being in Florida I can tell you that those holes are plugged on an awful lot of motors and they keep on going. Given long enough, the corrosion will build up enough in some areas that the pressure breaks the casting. I'd suggest cleaning it out the best you can, but not make them oversize because that may allow exhaust to blow out them and cause cavitation, or in the case of the one under the water pump allow air to enter, affecting the pump prime.

 

[Lostuzer]

Re: 1969 Evinrude 18 HP Fastwin Lower/mid unit water drain ports

Thanks JBJ,

For, ?Using different brands of primer and paint is a painting disaster waiting to happen.?
It seems I?d heard that somewhere before but never safely tucked away that tidbit of wisdom.

And thank you F R for good advice and the wisdom behind it.

I finally got the passageway open from question mark to question mark and as I was doing so noticed
in the lower area of the passage on the outside there is a bulge where the pressure had built up.
Who knows how long it had been clogged up in this almost 40 year old motor?