1975 Mercury 650 Throttle Question

We just recently purchased an older boat and are new to engine repair, so thank you in advance for any help. When we got the boat on the water the first time, it ran, but at full throttle it was very slow. The second time on the water, the reverse stopped working, so we decided to change out the cables. We read the manual and did everything it said to get the throttle set to the idle screw and shifter set; however, we noticed that when the shifter is moved to the most froward position, the throttle lever on the Mercontrol is only about halfway up, and there is a big gap between the lever on the engine and the throttle stop screw (see attached pictures). When bringing the throttle lever on the control up more, it doesn't do anything to the lever on the engine. Should there be a gap this big?

Also, can we know we can run the engine out of water with muffs, but can we put it into gear also to make sure the prop is turning properly?

Thank you for your help!

https://drive.google.com/open?id=0B4rpbSRLD49Dc3lvcFRKdFFRSnM4NVhnQnEwR1ZqTm16SEY4

https://drive.google.com/open?id=0B4rpbSRLD49DN1BHMlRYU1F6MzcwRlRtSUdlbmc5UUd1bXpv

https://drive.google.com/open?id=0B4rpbSRLD49DU3l3MVZpUzBYZFYtVWFwRWItQ3dxUlBWTm5B

https://drive.google.com/open?id=0B4rpbSRLD49DRzQ0RC1Ba3JoTTRON2JublRXSXQtRlk4RG04

https://drive.google.com/open?id=0B4rpbSRLD49DNFNzbHhkSjFUZUJsdXIzZTctanRuRGUwNDZV

Readjust the throttle cable until you get both full throttle and idle.

And neutral should be in the middle.

Jeff

That lever on the backside of the control is for cold start only and is only used when the control is in neutral to start the motor. It should be sitting flat when operating the motor.