I keep getting a warning beep and my engine cut power on my starboard engine. This has been ongoing ... the rpm on that engine is near 5000 while the other engine is much less around 4500-4600 range. When I had the port engine full throttle and the high rpm engine not even full throttle like 80-90 percent throttle. Could a throttle cable need adjusted or what would cause the rpm to be so high and hitting limiter at less than full throttle that side?

Engines have 300 hours on them all pressures n temps appear normal. Any help or suggestions?

Check your plug wires, I had a wire pop off and was down 3-400 rpm and the motor sounded flat and was lazy

the problem is the starboard engine is over revving hitting the limiter at 5000 rpm how can I prevent this

Could be a multitude of issues.

1) Make sure drive trim is adjauated so they both match on the indicators.

2). Make sure neither engine is in Guardian mode. You will need a scanner, SmartCraft, or software for this.

3) Borrow a pair of props and see if it still acts similar.
Same pitch would be ideal, but not required. One or both of your props could be bent.

4) Make sure both throttles are adjusted properly with the Merc Took, and are opening the throttle bodies fully and evenly. You will need a scanner or software to watch the TPS sensor value with ignition on, engine off.

5) You could have a neutral safety switch Issue too.