1967 80hp Johnson will not plane

[Tbone555]

Would would be the reasons for "not being able to plane". Runs well and idles well. Just acts like it has 1/2 power when wide open. Any help appreciated.
Thanks, Tim

 

[tashasdaddy]

Re: 1967 80hp Johnson will not plane

check compression, spark, fuel flow, clogged vent in gas tank, air leak in fuel line.

 

[F_R]

Re: 1967 80hp Johnson will not plane

More than likely it is runing at 1/2 power because it is running on only half the engine...that is it is running on two cylinders. The usual trouble shooting procedures apply, check compression, spark and fuel.

The carb is two barrel, one feeds two cylinders and the other feeds the other two. Each has it's own high speed jet, so if one jet is clogged, you run on two cylinders.

I don't have the book on a '67. Does that still have the battery ignition with points? If so, there are two sets of points. Same deal as the carb jets, one set of points fires two cyls, other set fires the other two cyls.

 

[Tbone555]

Re: 1967 80hp Johnson will not plane

I wanted to thank you guys for the suggestions for sure!! I am in the process of buying this boat and this is all that is found wrong with it. I just wanted to make sure it was not something that is going to take a new motor right off. Any further suggestions appreciated. Tim

 

[Chris1956]

Re: 1967 80hp Johnson will not plane

Tbone, Those guys just cited the possible problems. I recommend you do a compression test on all four cylinders. if compression differences are 15% or less, it is likely the motor can be fixed up for a reasonable price. Remember this motor is 40 years old.