1968 20hp johnson wont run with full power at full throttle

[phillipramsey]

im having some problem with my '68 johnson 20hp motor. ive replaced the coils, condensers, and plugs and it starts and idles fine but when you open it up it doesn't run at full power but every once in a while it will shoot to full power then back down. im not sure but it seems as though its not firing on both cylinders all the time? what do you guys think it might be? the only thing i can think of is the plug wires but only because thats the only thing i havent replaced yet.

 

[jbjennings]

Re: 1968 20hp johnson wont run with full power at full throttle

My vote is for plug wires and/or dirty points. I also wouldn't exclude the possiblity of a bad coil even though it's brand new. I've gotten a brand new one before. Not likely, but possible.
JBJ

 

[phillipramsey]

Re: 1968 20hp johnson wont run with full power at full throttle

the plug wires fixed it! thanx man