Vintage Johnson

Ithica DB

Seaman
Joined
Apr 19, 2011
Messages
62
I have the boat that I grew up in. This boat is I think 1963 Starcraft 14' sea scamp with a 1955 Johnson 10hp sea horse with two pressure tanks. It has been in my boat house for thirteen years. I started it once about 6 years ago. I decided to give it a try this weekend new gas and gas lines one pull it fired and second pull it started unbelievable.
I have some questions is the motor worth anything? where would I find a new prop and what is the gas oil ratio for 1955?
I like having a reliable boat sitting around I havent had to put a dime in, as for my newer boats MONEY PITS
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: Vintage Johnson

No collector value; too many still in regular service. Tells you how good they are.

Fuel mix is officially 24:1, but you will get advice everywhere from 16:1 to 50:1. Were she mine she would dine on 24:1.
 

kfa4303

Banned
Joined
Sep 17, 2010
Messages
6,094
Re: Vintage Johnson

Hi itihica DB. These old OMC 10hp are great motors. Pound for pound they're one of the strongest around. Assuing the comression is decent, i'd say it's well worth the effort. If you don't mind spending about $150 uprfornt to replace all the consuamble parts, you'll have a great motor for years to come. A new carb kit, impeller(waterpump), spark plugs and spark plug wires, tune up kit (points and condensers) and she'll be all set. you should be able to get almost all of what you need right ehre at iboats. Here's a great link fo these 10hp. Be sure run 16:1 fuel:eek:il mix. They didn't go to 24:1 until the early very late '50s/ earl 60's. plus, it never hurts to have a little extra oil rather than too little. Don't worry if she smokes a bit, that's normal. Also, be sure you only ever run in the water or a test tank. Muffs will not work on these older models so you'll need an old garbage can. Fill the water to about and inch or so below the exhaust port. Keep us posted. We love pics.

http://www.sschapterpsa.com/ramblings/johnson_QD.htm
 

1946Zephyr

Vice Admiral
Joined
Oct 21, 2008
Messages
5,556
Re: Vintage Johnson

As JB says, that old 10hp will do good on 24:1 The old 10's were built with needle bearings in the crank and rods (except wrist pins) since 1949. So, they'll run good on 24:1. The 7.5hp and smaller all had babbot bearing rods and brass bushing crank journals, so you do want to at least stay with the 16:1 mix on those.
Awesome old motors. As kfa4303 says, it'll last you for many years to come, if you go completely through it and give it a good tune up. New impeller, new carb kit and new ignition system. You also want to check the oil in the lower unit and make sure there hasn't been any water intrusion in the oil. The old 10's prior to '58 had the larger 5 bolt lower unit and those were the same as the 15's and 18's had in that era. Much better than the lower units on the '58 and newer I think.
 

Ithica DB

Seaman
Joined
Apr 19, 2011
Messages
62
Re: Vintage Johnson

Thanks for the advice.
I did drain lower unit it was like mud. I noticed it said fill with Hydrponic (spelling) oil I used a standard gear oil is that ok?
Is the tune up something I can figure out or do I need to buy the parts and get some one to do it. I haven't researched the parts yet. They still make parts for these old motors? I had thought once it quits I would be done unless it could be retro fit.
I am pretty handy if I can look at something and figure it out not real good with manuals. I am the guy that throws installation instructions to the side.
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: Vintage Johnson

Only after you get it will you realize how badly you need the OEM Service manual, Ithica.

www.outboardbooks.com
 

JasonAych

Petty Officer 1st Class
Joined
Aug 10, 2008
Messages
274
Re: Vintage Johnson

The bushing in the wrist pin is a weak spot on these. If I am not mistaken there are bushings at the each end of the crank as well. I'd recommend 16:1 or at least 20:1. 24:1 is starting to get away from my comfort level.
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Re: Vintage Johnson

I have a QD16 myself, restored, great motor. One I will not sell.

As JB and Zephyr stated, 24:1 fuel oil mix. It is a fairly easy motor to work on, compared to others. Go to ebay and get a factory OEM service manual. Not a clymers or seloc. If you need any help with the QD let me know, or pics, I have it in my basement.
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: Vintage Johnson

My 67 after market manual indicates top,lower,crank pin are roller bearings.Center is bushing.
24:1. Same section 7.5 is all bushings and is at 16:1.
These old crocks have been around a long time at 24:1. I think we're safe at 24:1
 

Ithica DB

Seaman
Joined
Apr 19, 2011
Messages
62
Re: Vintage Johnson

Thanks for the help once again. Keep your eyes peeled I anm sure I will be needing more help in the future. Too many projects and hobbys and not enough time. I will start this after a floor project in another boat.
 
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