Antique 5 h.p. motor identification. Johnson Seahorse

[Doug Redinger]

I am trying to identify and learn a little bit about an old Johnson outboard I just bought for $ 25.00. I am a collector of old Mercury outboards mostly, But I just couldn't pass up this little 5 h.p. Johnson. It is mostly darker green colored. It is a 2 cylinder, and I believe it to be water cooled although I think the impeller is shot, as it did not pee when I started it. A small amount of steam came out of the pee hole in the water-line fitting.

Serial number is 99-4090 and beneath the serial numer was the letters
TN 28

Any information or advice about restoring the old motor to running condition would be greatly appreciated.

 

[Scaaty]

Re: Antique 5 h.p. motor identification. Johnson Seahorse

Got ya a prize..the TD's and TN's is the most solid motors made...run 24-1 oil...
That said, 28 is a 52/3..someone here or I will later get ya the current year as ya gave the S/N)
I would HIGHLY suggest popping the Flywheel, ...coils probably cracked and junk..known prob....pop the lower too, impeller easy change..
Stick with this thread on it...we (and me) are old Johnny lovers....we can get ya up and smoking ..( also do a compression check...and post it..Good Luck..

 

[wbeaton]

Re: Antique 5 h.p. motor identification. Johnson Seahorse

The TN-28 was built from 1952-53. Yours was built in 1953. I'm not familiar with that motor so I can't tell you where the water exhausts. But I guarantee it has an impeller. I would guess that it exhausts some water out the exhaust relief slot just above the lower unit at the waterline. The rest would go out underwater.

Oh, and my advice...run it and love it.

 

[Scaaty]

Re: Antique 5 h.p. motor identification. Johnson Seahorse

The TN-28 was built from 1952-53. Yours was built in 1953. I'm not familiar with that motor so I can't tell you where the water exhausts. But I guarantee it has an impeller. I would guess that it exhausts some water out the exhaust relief slot just above the lower unit at the waterline. The rest would go out the underwater.

Yep..If ya want to see if the water pump is OK, follow the Tiller handle back to the motor. NOW, go back a few inches, and on the block there will be a lower screw about 1/2 inch...flat blade screw type. Fire it up in a garbage can...loosen/remove that screw...water washes your socks, your ok...
NO pee hole...just a good mist out the lower leg, (IN WATER..LIKE A G-CAN)..out the mass of small holes that will be just under the transom clamp, facing the front
Need to edit this...I was thinking a 3 hp Johnny "Weedless"...I can't remember the TD/N's...had a few, but sold them all off. They might be similar though..

 

[Doug Redinger]

Re: Antique 5 h.p. motor identification. Johnson Seahorse

Popped off the flywheel and the coils and points, condensers, etc. looked like brand new. Tested for spark and both plugs had a good blue spark, although I am not sure if they are firing a true 180 degrees from each other. I made a sync plate so I will check that next. The water pump does work, I just didn't have quite enough water in the barrel the first time I fired it up. It's spitting water out through a 90 degree fitting on the water line pee hole now. Got it to run for quite a few minutes late last night before going to bed. One thing that puzzles me is what the needle does that projects up into the front crank-case half. There is a small hole ( about a 1/4 " diameter ) that looks like it goes right into the crankcase on the front part of the crankcase. The needle projects into this 1/4 " hole. Turning this needle in or out greatly affects how the motor runs or if it will start. What is the purpose of this needle? I am a Mercury man and I have no Idea what this needle does. I am going to check the lower unit tomorrow. How difficult is it to locate seals, carb kits, etc. for a motor of this age? Will do a compression test tomorrow and will post results then. Thanks for all the great information and responses!

 

[Doug Redinger]

Re: Antique 5 h.p. motor identification. Johnson Seahorse

Compression test revealed 65 psi in both cylinders. Engine runs but will probably be difficult to tune up and when trolled way down it seems to stall.

 

[Jpoter]

Re: Antique 5 h.p. motor identification. Johnson Seahorse

I have what I believe to be a 1948 white mercury 5hp Merc 110 serial # 1492555 made by the Kiekhaefer Copr. from cedarburg, WIS and am possible interested in selling. After further research on company have found out that they only manufactured from cedarburg, WIS from 1939 to 1944 so engine must fall within those dates-ser. # is 1492555-If anybody has more info please let me know-Thanks!