1976 Johnson Seahorse 25hp

[Twin350]

Hi everyone

I just joined this site because i recently purchased a pontoon boat with a 1976 Johnson seahorse 25HP. The motor had not been ran for about 3 years, so i cleaned the carb, changed the gas, put new spark plugs in it, filled up a Gas can with 93 octane and added a little sea-foam to it. After about 3 pulls it started right up. After a few times out on the water the motor would go into Forward, but then the prop would not spin. Then i put it in reverse and started going and then it stopped spinning the prop. I have not done much work with boat engines at all, but have some experience in other 2 stroke type motors. I was just wondering if you guys could get me going in the right direction before i start tearing into it to find the problem.

Thanks Alot,
John

 

[Daviet]

Re: 1976 Johnson Seahorse 25hp

Did you mix oil with the gas?
Does the engine rev up, maybe you spun a prop hub.

 

[Twin350]

Re: 1976 Johnson Seahorse 25hp

Did you mix oil with the gas?
Does the engine rev up, maybe you spun a prop hub.

Yes I mix 50:1. The engine revs up, but when its in gear the prop does not spin. You know when the engine is off and in gear the prop is harder to spin, sort of like when a dirt bike is in gear and your trying to push it without the clutch in? In that case the prop is easy to spin, like it was in neutral.

 

[Daviet]

Re: 1976 Johnson Seahorse 25hp

Check the drive pin #54 below.
http://www.ishopmarine.com/ishop/js...CatFilter=BRP&eCatSupFldr=supplier-100-005-EJ

 

[Twin350]

Re: 1976 Johnson Seahorse 25hp

Check the drive pin #54 below.
http://www.ishopmarine.com/ishop/js...CatFilter=BRP&eCatSupFldr=supplier-100-005-EJ

Alright Thanks. If there is any other suggestions out there, feel free to throw in your 2 sense!!

 

[2manband]

Re: 1976 Johnson Seahorse 25hp

Check to make sure that the shift rod is connected. It's parts 6, 7, and 8 in the diagram linked above. You can access it via a little door in the exhaust housing that's held on with two screws.

If you have no luck there, it might be the clutch dog. (#31) if the teeth on that get worn, it can pop out of gear and back into neutral.

Does the shift lever on the powerhead move back to neutral when it stops spinning the prop? If so then my first suggestion is probably out, and the second would be more likely.