1970 Evenrude 115 Idles great but jerks and shakes at half to full throttle

[Rusted Rutter]

Hello I am new to this forum and I have read till my eyes hurt. I have read lots of problem but none like what I am experiencing.
:yield:

I have a 1970 evinrude 115 115083D that will run and engage in gear just fine. I took it out on the water this summer and noticed I could get it to go to full throttle. I backed it off to about half .... ran smooth and no sign of trouble other then no full throttle... Then out of no where BOOM the shaking and jumping came back... backed it down to an idle and ran fine till I got it out of the water and back to the dock, I even stopped and pulled another boat who was having trouble behind me.... Does anyone know what this problem is I'm having. It wouldn't die but would stay running but would shake the whole boat.

 

[Bosunsmate]

drain and check oil for metal parts.
sounds like gear problems

 

[Rusted Rutter]

No no gears are grinding, oil is clean, I know what it'd feel like if the clutch dog was slipping....it was more of a missing but the plugs were new

 

[Bosunsmate]

boom and shaking and missing is often the clutch dog wearing out.
no full throttle and a boom will then check compression

 

[racerone]

Run with a timing light hooked up.---May help in deciding ignition problems and which cylinder.-----You might want to remove the flywheel and clean distributor cap and rotor.----Replace the wee rubber boots on the wires where they screw into the cap.