No Motor Power

[Mikecrawfish]

I have a 1960 Johnson 18 hp I bought "as is" and it ran in a barrel. It starts on 1 pull with choke out. It runs in gear, but does not go any faster when I push the gear arm in all the way. The shifter is moving all the way back, but the motor will not run any faster. It will run at the same speed as long as you want and will not stop running until you hit the kill button. Why won't it pick up speed?

[boats.net]

Inspect the mechanical linkage to see if anything binding or stuck.

[boats.net]

Make sure the throttle is moving the timing plate that the carburetor accelaration linkage roller rides on.