1969 25 hp Evinrude high speed timing issue

[BlackoutBill21]

ok so... got my new project on the water today. Ran beautiful. Go to take it to full throttle and it dies runs crappy and surges. Playing around with it I discovered some things. It ran best right before the throttle hit the full open tab on the flywheel.

Now here’s where it gets interesting. If I kept the throttle backed off, and opened the throttle with my finger... BOOM full speed awesomeness.

Now to to make things more complicated, after a while of running full speed ( throttle 80% finger holding down throttle arm) the motor would start to possibly overheat/ stall and would not re start unless it sat for about an hour.

This thing has a new impeller, and was gushing water the whole time on the water... ( I’ve had bad luck in the past and always check )

Im gunna pop the flywheel off and check some thing... anyone got any ideas? I’m gunna post A yountube video soon to show everyone

 

[Chinewalker]

max advance should be governed by a notched plate on the underside of the magneto plate. Starboard side, where the shift lockout lever is moving around. Possible the lever has gotten sloppy and allowing too much advance, or not meeting the notched plate at all.