throttle problems

[basso]

I have a '93 Merc 150 EFI. If I leave my hand off the throttle handle the motor will slowly decrease fro 5000 rps to 3900 rps and stay there. My hand must be on the throttle to keep the rps up. thank you basso

[boats.net]

Some control boxes have a throttle friction screw to set more tension on lever, what style control box do you have?

[michaelreich]

I have the same problem. My boat is a 1993 Mariah Barchetta with a 4.3LX Mercruiser. The control says Quicksilver on it, but does not have any model numbers that I can see.

I called the 877 number and they told me to post here.

I have attached a picture of it.

Please advise where I can get parts.

Thanks,

[boats.net]

There is a screw on side of controls that says friction, need to tighten a little.