1969 40 Johnson Supersea Horse

[The Starcraft Enterprise]

Hey,

I have some issues. I bought this boat and motor late last season and only used it 5-6 times. I even had it serviced right after I bought it. The motor ran great until the last boat outing. I would have the throttle floored and the motor would just lug and go very slow. After that I stored the thing for the winter leaving half tank of gas in the tank.

This year, I topped the tank off with newer gas and changed the spark plugs and its still giving me crazy symtoms like last year. Any thoughts? dirty carb?

 

[Daviet]

Re: 1969 40 Johnson Supersea Horse

Do a couple of simple tests first, check the compression and spark to see if you have a dead cylinder.
If those check out, might be time to overhaul the carb.

 

[The Starcraft Enterprise]

Re: 1969 40 Johnson Supersea Horse

what if I have a dead cylinder?

 

[Daviet]

Re: 1969 40 Johnson Supersea Horse

Depends, if you no compression, you need to pull the cylinder head and see what's wrong. Maybe a defective head gasket. If you have no spark you will have to pull the flywheel and check out the ignition system.