Old 3 HP Johnson Sea Horse

KwickLabs

Cadet
Joined
Jan 6, 2008
Messages
7
Hi, I just found this forum surfing for some info on my son's 3 HP Johnson Sea Horse. It is a JW-10 which is the 1952-54 model. It starts and runs fine, but the gas cap is cracked and leaks badly when the motor is tipped up. I told him I'd search for a replacement. I'm not doing very well. :D

Any ideas would be appreciated. :)

Regards, Jim B.
 

samo_ott

Vice Admiral
Joined
Jun 18, 2006
Messages
5,125
Re: Old 3 HP Johnson Sea Horse

I have the exact same engine. This forum is more for help than parts. I would try the www.aomci.org site as they cater to the older engines and the classifieds are pretty good.
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Re: Old 3 HP Johnson Sea Horse

Another useful site for parts for the older motors is "http://www.laingsoutboards.com/newpage4.htm"
 

KwickLabs

Cadet
Joined
Jan 6, 2008
Messages
7
Re: Old 3 HP Johnson Sea Horse

Thanks Steve and High Trim. :)

I did a quick look at both of those links. They are definitely going to help.

Steve, you have the same engine. Greg likes all the comments he gets about his. However, he changes the lower unit oil about every five tanks of gas (water gets in). Is that normal? I told him the seals or whatever must not be very good anymore. The link to parts should help with that. Thanks again.

Jim
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Re: Old 3 HP Johnson Sea Horse

Is he changing the gaskets on the drain and vent screw every time? That is the number 1 spot for water intrusion. If not I would replace them, then run it again to determine if the leak is fixed. If there is still water intrusion, he will need to pressure test to determine exactly where the leak is, or simply replace all the seals. Steve will definately be 1 of the guys to talk to on here about the older motors. Good luck.

Just for future....

To pressure/vacuum test a lower unit:

a) drain the gear oil
b) use an appropriate adapter with a gauge tee'd in to apply pressure or vacuum. No more than 15 psig for pressure. You can use a bicycle pump or any other compressed air source for pressure. For vacuum, you need a vacuum pump.
c) LU should retain some pressure or vacuum for 45 minutes minimum.
d) If pressure doesn't hold, submerge LU in water to find leak source [possibilities: drive shaft seal, prop shaft seal(s) (usually two), shift shaft seal and the fill/drain screw washers.]
e) replace offending seal(s) as required.
 

samo_ott

Vice Admiral
Joined
Jun 18, 2006
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5,125
Re: Old 3 HP Johnson Sea Horse

I have the engine but actually have not got it in the water yet... it's on a long list of things to do... But for any engine there should not be that kind of water infiltration so do as HT says...

But in the meantime, changing it regularly is a good thing to prolong the life... also consider using synthetic LU oil (I know it costs more) as it's supposed to work much better than regular oil when it's been compromised with water...
 

KwickLabs

Cadet
Joined
Jan 6, 2008
Messages
7
Re: Old 3 HP Johnson Sea Horse

Wow! It looks like I came to the right place. Thanks again. :)
 
D

DJ

Guest
Re: Old 3 HP Johnson Sea Horse

Check Twin City Outboard for a cap. They are on Google. I know they will have one.
 

Scaaty

Vice Admiral
Joined
May 31, 2004
Messages
5,180
Re: Old 3 HP Johnson Sea Horse

GREAT old motors..have 3. Bulletproof.
I have a good lower (weedless..angle drive) that I switched out on one, for a later straight drive.
And a day late on a cap..just sold my last one. Keep an eye on Ebay...
Interested, PM me, or email me .. hogrider@myway.com put 3hp in the sub line.....
 

tmcalavy

Rear Admiral
Joined
Aug 29, 2001
Messages
4,005
Re: Old 3 HP Johnson Sea Horse

Can't remember what kind of seals are in the LU of those little Johnsons from the early 50's. If it is losing regular marine LU lube/oil regularly, consider using Lubriplate 105 white engine assembly grease instead of the more fluid LU oils. Those older LU seals really weren't engineered for modern LU lube/oil. The Lubriplate will not emulsify with the water and thin and run/leak out. You can find Lubriplate at just about any auto parts store.
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Re: Old 3 HP Johnson Sea Horse

As tmclavary said, the seals are different now than they were in the 1950's. So if he does do the seals dont be surprised to see they are a bit different.
 

BillP

Captain
Joined
Aug 10, 2002
Messages
3,290
Re: Old 3 HP Johnson Sea Horse

If changing seals make sure to change the one under the waterpump too...and check the shaft surface where it rides. If rough from corrosion it will continue to eat seals.
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Re: Old 3 HP Johnson Sea Horse

Gearcase and waterpump

help1.jpg

Carb

help2.jpg

Step by step explanation of how to fully tune that motor up. May be useful to you. Good luck. Just copy and paste with the "" ""

"http://www.maxrules.com/fixtuneitup.html"
 

BillP

Captain
Joined
Aug 10, 2002
Messages
3,290
Re: Old 3 HP Johnson Sea Horse

The seals you want to change in those pics are called "oil retainers"...one is on the prop shaft and the other under the waterpump assy.
 

supercoolbabe

Petty Officer 2nd Class
Joined
Jun 5, 2008
Messages
103
Re: Old 3 HP Johnson Sea Horse

I have the same motor. Please let me know where you have success. Thank you
 
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