1960 Johnson 40 hp not quite running right....

[Biggwaukegan]

New to boating, and definitely new to this Johnson motor. Took it out on the lake the other day and it ran fine, but didnt seem to be putting out the horsepower a 40hp motor should. Granted its 47 years old but there are new plugs and coils, all the lines in the motor were replaced right b4 I bought it. I have heard of sometimes these motors having a gasket or something glued in by the prop. They wear out over time I suspect. Anyone know if this could be the problem or what the problem is? Please help me on how to fix this boat motor. Thanks

 

[CATransplant]

Re: 1960 Johnson 40 hp not quite running right....

What kind and size of boat is this on, and how, exactly did you determine that it wasn't producing enough power? If you can describe, in more detail, what happened on the water, it will help. Did the boat plane? Did the engine seem to bog down?

The more info you provide, the better we'll be able to help you.

 

[Chris1956]

Re: 1960 Johnson 40 hp not quite running right....

Depending on the boat's size and weight, that motor will only push a 15' boat at 25-29MPH, with the proper size prop in good condition. At 47 years of age, with whatever prop is on it, what performance are you getting?