throttle creep

I have started to have a bit of throttle creep. She seemd to back off after a while of cruising at the same RPM.

What should I look at? Linkage? Cable? Every thing seems to look fine

Sd

The whole thing being loose or a return spring.

doesn't have a spring. Just a Mores cable to the throttle linkage.

It doesn't happen all the time. That is what has me puzzled.

SD

Filter?

THere is sometimes an adjustment for friction at the side of the control handle head. SOme are easy to adjust , some not. Often a screw head that appears to have no other purpose such as holding a cover in place is the adjustment.

Sometimes there are parts that need to be replaced. That's the case with my older Morse unit. The cover comes off and there are some plastic bushings and washers that must be replaced when they wear too much which of course requires a bit of disassembly.

If your control head is a Morse unit you should be able to go on line and figure out which unit you have or if you are lucky the thing may be marked under the cover. They made a lot of them. Then order parts.

And before I forget check the clamps that hold the cable end barrels, both ends. If those clamps are loosening the whole cable end may actually move a bit causing a change.

I had the same issue with my previous boat
Running at 2000rpm ,after 1/2 hour or so it could drop to 1925
3 station Morse controls were high enough effort,so I did not want to tighten the tensioner on the head

1/2 a wooden clothes peg used as a wedge between the throttle handle and case worked great for a few years until I replaces the whole system with mmc electronic controls

What kind of engine

If it is a Detroit the governor has a large adjustable spring that hold throttle position. The spring is about forty bucks and takes a little time to adjust. The throttle will creep and not stay in position without it.