Motor question

General Boats and Motors
1

Found an old 20 hp Johnson Sea Horse in my uncles garage. He gave me the motor and said he thought the starter was burnt up. Any idea on the year of this outboard?
Thanks.

2

The motor is a 1970 model. If it’s the starter there is still the rope starter that can be used. Although there are a few things you should do before trying to turn it over.

Hope this helped
David H.

David H.

3

GameRunner, thanks for the input. PM sent.

4

With the help of a good friend(retired airplane mech) got the motor starting and running very good for sitting over 15 years. Barrel test satisfied us and mounted it on a jon boat to water test…whopping 6.9 mph:roll_eyes:

I was hoping for a little more speed. Getting a new skiff and the 20 hp Yamaha is being traded up, so I am stuck with this motor to power my river/duck boat.

Any suggestions would be helpful. Getting it running was step 1.

Thanks

5

Definitely replace all rubber parts (fuel hoses, carb gaskets, etc) with alcohol resistant stuff. A water pump and foot oil change too.

6
quote:
Originally posted by Reel Karma

With the help of a good friend(retired airplane mech) got the motor starting and running very good for sitting over 15 years. Barrel test satisfied us and mounted it on a jon boat to water test…whopping 6.9 mph:roll_eyes:

I was hoping for a little more speed. Getting a new skiff and the 20 hp Yamaha is being traded up, so I am stuck with this motor to power my river/duck boat.

Any suggestions would be helpful. Getting it running was step 1.

Thanks

are you sure it's running on both cylinders?
7

I assume so. Compression was 120 and 125.

All hoses, etc…replaced

8

did y’all disaasemble and clean the carbs and verify that all of the jets are clear? did you try to add choke to see if it would run better or worse? just seems it should do better than that.

9

Carbs were cleaned. Only water tested it for a few minutes so I will give it another try. Thanks.

10

With that good of compression something is wrong. Any 20hp - no matter how old should run a lot faster than 7mph?

J Ford

http://www.joinrfa.com/

11

Jford, thanks for the diagnostic:wink:

23 mph today. Another set of plugs and little WD in the carb. Seemed the choke was sticking. Going to keep running and hope it stays consistant…the Yamaha will be heading to Ft. Pierce in a few weeks.

Thanks