1968 40hp johnson wont push my boat.

[Nhayes0027]

My 1968 electric shift 40 horse johnson will only get my boat up to about 12 mph. I ran it in auto choke all day without thinking to try it with choke off. could that be my issue?

 

[Nhayes0027]

Boat is 14 ft fiber glass.

 

[racerone]

Check for spark on both leads.----Spark will jump a gap of 5/16" on a good magneto.

 

[Nhayes0027]

Just put new plugs in it. Both seemed to be fouled pretty bad.

 

[racerone]

Your best bet is to test stuff.---Does spark jump a gap of 5/16" , yes or no ?