Outboard lower unit interchange

-
V

volaredon

Well-Known Member
Joined
Feb 28, 2010
Messages
3,554
Reaction score
2,004
Location
IL
I have a 1963 Evinrude fastwin 18hp short shaft outboard, model 18302, that I cannot get to stop mixing water in the lower gearcase. I've tried a new skeg (fin) new seals, ended up replacing the prop shaft bushings and seals as the original fin was cracked. I believe now that the fin and the main gear case housing are machine fit to each other and mixing means not matching, and not sealing. So I've decided to fix it once and for all, in finding a complete lower unit from another outboard.
What years and hp models of Evinrude and Johnson have lower units that will swap out with my original?
I do intend to replace all of the seals and gaskets on the replacement lower unit as well as a new impeller. As far as I know the one on there is original from 1963
 
Boy I don't know without part numbers or casting numbers, and I don't have any of my old books immediately available (fire cleanup) and some are just plain missing in action. But they are gasketed with a thick "rope" neoprene seal, and I would suspect chineseoization rather than matching. I did look up one or two of the online exploded parts views, and the gearcase IS sold as a "pair."

www.crowleymarine.com

GEARCASE GROUP - 1968 Outboard 18 18802A | Crowley Marine

View parts diagrams and shop online for GEARCASE GROUP parts, 1968 Outboard 18 18802A. Offering discount prices on OEM parts for over 50 years. FAST $4.95 shipping available.
www.crowleymarine.com www.crowleymarine.com

You also might try "the right stuff" or other recommended sealer. Do you know where it's leaking? You can device a pressure/ vacuum tester by using a fitting in the drain/ filler plug. Then you can do a bubble test just like a tire. Don't forget the gasket for the little screw in the very bottom for the shift fork. It can leak.
 
I think what I'd do is look for an original or reprint parts book, then take those numbers and plug into Google and ebay. There are folks selling that sort of thing on there fairly regularly
 
volaredon said:
I have a 1963 Evinrude fastwin 18hp short shaft outboard, model 18302, that I cannot get to stop mixing water in the lower gearcase. I've tried a new skeg (fin) new seals, ended up replacing the prop shaft bushings and seals as the original fin was cracked. I believe now that the fin and the main gear case housing are machine fit to each other and mixing means not matching, and not sealing. So I've decided to fix it once and for all, in finding a complete lower unit from another outboard. What years and hp models of Evinrude and Johnson have lower units that will swap out with my original? I do intend to replace all of the seals and gaskets on the replacement lower unit as well as a new impeller. As far as I know the one on there is original from 1963
Click to expand...
67Dart273 said:
I think what I'd do is look for an original or reprint parts book, then take those numbers and plug into Google and ebay. There are folks selling that sort of thing on there fairly regularly
Click to expand...
 
I found one of a 66 model year Johnson 20 HP that "looks right" by the eBay pic but I don't wanna buy it and have it be wrong.
 
You must log in or register to reply here.
-

Back
Top