Johnson lower unit identification??

[Drowned Rat]

Hi guys. Can anyone identify this lower unit by approximate year model. I believe it came off a 35hp OMC product and I'm guessing it's a late 50's early 60's unit. Obviously black is not it's original color. The drive shaft has about 10 or so splines, not 4 large ones like I've seen on smaller outboards. It does have the phillips screw "Pin" in the lower part. It does not have water intake on the sides like modern outboards, it's on the trim tab looking thing at the rear under the cav plate. Also, assuming this came off a 35hp engine, how can I tell what other hp models it would fit? Thanks for the help!!

http://i7.ebayimg.com/04/i/000/96/ec/cac6_1.JPG

 

[F_R]

Re: Johnson lower unit identification??

That unit fits a whole raft of different motors. The main thing to look for is whether you need a single water tube or two tube. The one in the picture is single. It fits 22,25,28,30,33, some 40s. higher horsepower models use a different pinion gear and bearings than the lower hp. Does it have a threaded prop shaft/nut? That would be a clue too.

 

[Drowned Rat]

Re: Johnson lower unit identification??

Thanks FR. The prop shaft is threaded for the prop nut only. The prop itself just slides on and is kept from turning by a pin. Any idea what year this might be?

 

[BoatBuoy]

Re: Johnson lower unit identification??

I just today finished a reseal and water pump on my '57 35hp. Before that I did the same on my '56 30hp and although I didn't count the teeth on the gears, I can say they are ABSOLUTELY identical. Like Frank said, they used the same for several years. I found the one you're looking at on ebay and I see no difference in it and my 2 - even the end of the driveshaft. Pick a number.

 

[Drowned Rat]

Re: Johnson lower unit identification??

Thank you guys, that's the info I was looking for.

 

[CATransplant]

Re: Johnson lower unit identification??

Now, I'm not sure what they did in big twin models in the 60's but my 1958 Johnson Super Seahorse was the first year they had the two water tubes. Non Super-Seahorse models the same year had the single tube.

I believe, but I'm not certain, that all the Big Twin models after 1958 had the double water tube design. That would put yours 1958 (old style) or earlier.

 

[F_R]

Re: Johnson lower unit identification??

OK, not absolutely certain on this, but I think the 1957 was the last one to have the threaded nut. So that still leaves the possibility that it is a 35 with the stronger pinion bearing, or a 25 with the taper bearing. Just for the record, the single water tube style was revived and again used on the 40hp of the 1970's, as well as the 28 and 33 in the '60s. But those would have the keyed nut. It was also used on Gale motors thru 1963. A VERY popular unit!

 

[Drowned Rat]

Re: Johnson lower unit identification??

Appreciate the help! Have a great day.