63 johnson not running right

[powerwagon]

Need some help guys !!! i have a 63 johnson 40 hp model #RDS 40D. the motor seems to buck or jump up. About every 6-7 seconds, no matter what speed. you can feel it through the boat. and the thing uses a lot of gas. went about 6 miles on 4 gallons of gas at half throtal dosn't seem to leave any gas streaks in the water.Idels good, and runs good for the most part except for problem above. one more thing about how fast should this motor move a 17 foot lonestar fiberglass? Thanks for any info!!!!!!

 

[jonesg]

Re: 63 johnson not running right

Your message is already scrolled back to page 4 so its not going to get any help as posted.

Baseline it,
get some readings for compression,
spark gap test and try a timing light on the plug wires when it bucks.

Post the results and we'll have something to work with,

otherwise its all just speculation , opinions and guesses.

Go to autozone , get a compression guage and spark gap tester, they're cheap. A cheap timing light will work.