1957 35 hp Johnson Seahorse.

[Hillbillywill]

Ran my "new" 1957 Seahorse for the first time last week. She ran like a champ for about 40 minutes and then began to loose power, ran her for another 10 minutes or so and then limped back to the dock. Once home, I noticed that she had burned a lot of gasoline. Pulled the plugs and they were black and oily. Checked the compression and it was down on both cylinders. She was pumping water well and the impeller is fine.

Am I running my mixture to rich (currently 32:1) or does the carb need to be leaned out? Should I run her lean to lean for awhile (50:1)?

thanks all.

 

[F_R]

Re: 1957 35 hp Johnson Seahorse.

ALL 1957 Johnsons have bad coils unless they have already been replaced. Remove the recoil starter, then the inspection cover from the flywheel, and peer in there. What do you see? Cracked coils? or dirty, oily, breaker points? You are wasting your time if you don't correct those things.

Correct fuel mixture is 24:1. So you certainly are not too rich at 32:1.

 

[Hillbillywill]

Re: 1957 35 hp Johnson Seahorse.

engine has new points and coils. And yes, I meant 24:1. 16 ozs to 3 gallons of fuel.

 

[kfa4303]

Re: 1957 35 hp Johnson Seahorse.

Great motor you got there. I'm jealous I'm inclined to agree with F_R. Spark is relatively easy to check and fix if need be. However, if the compression really is low (how low is low btw? They should be around 100 psi and be within 10% of each other) on both cylinders then you may have a head gasket issue. Here are some handy links that may be of some use.

http://www.marineengine.com/parts/v...ntage-evinrude-johnson/377023/37702300001.htm

http://www.duckworksmagazine.com/04/s/columns/max/24/index.cfm

http://www.outboard-boat-motor-repa...on 3 HP 1952-1967 Ignition System Tune-up.htm