1969 evinrude 40hp Eletric shift throttle issues

[Alexmck]

Hey guys first post here. Ive seached everywhere and came up with nothing. So i bougbt this motor used and put it on my 1961 crestliner Admiral 16ft aluminum. My problem is when I throttle up fully it seems to only do about half throttle then it will jerk to full throttle for a few secs then go back down . if I pull on the actual cable it self a little it will sorta act right. This is my first boat and was fun when I got it up to speed but it seems random. When I pulled on the cable a little spark came out. One of the little plastic caps that goes on inside the cable is missing and its metAl on metal. Sorry if this doesn't make since. I just need help I wanna take the family out boating before it gets cold. This problem is at almost any throttle position

 

[Alexmck]

I ment to say the throttle box may be giving me issues but I'm almost clueless at this point

 

[Joe Reeves]

Spark plugs on that model should be Champion J4C or J6C plugs gaped at .030... due to age, I'd go with the J6C plugs.

I assume that you're saying that the rpms will change like you were turning a switch on (or off), and if so... that's an ignition problem.

First thing to do is to check the compression... what are the individual psi readings of both cylinders?
Second thing... remove s/plugs, rig up a spark tester that you can set a 1/4" air gap for the spark to jump across. The spark should be a strong blue lightning like flame... a real SNAP!

Faulty spark can be caused by improperly set points, dirty points, a cracked or simply a weak coil, a plug wire shorting out, a bad condenser... many things.

You'll need a flywheel puller that incorporates 3 bolts that screw into the 3 threaded holes you see surrounding the flywheel nut. Also a foot pound torque wrench to tighten the flywheel nut to a torqued 105 foot pound tightness... anything less will result in a sheared flywheel key.

 

[Alexmck]

Intermittent rpms like 40% then jerks to 70% at the same throttle position. I bought the motor from a friend and it worked great for him on his boat. Since when I touch the throttle cable( little bit of cable showing. Stretched some) it shocks me Could that be a wiring issue?

 

[Alexmck]

Also if it helps I do not have the auto or electric choke. Hooked up to the ignition. Ive Been using auto choke on the motor