Engine losing power

[Sundancer280]

Alright I got a good one today. So after getting on plane, my 05’ sundancer 280 4.3L will run perfect for a solid 5 minutes. I would be at a cruising speed (30 mph) with about 4K rpm’s for each engine. A few minutes later, I’ll start to see a drop in rpm’s in my left engine, and will drop to about 3.5k rpm. The only way I could stay cruising at that point is having my left engine run at 3.5k rpm while my right engine run at 4.5k rpm. Otherwise the boat will have a hard time running. What the heck is going on here and why isn’t my left engine running over 3.5k rpm after running 4-4.5k for about 5 minutes just fine.

 

[JimG]

Can you add throttle and bring the RPM's back up? Or are you already at WOT?

 

[Sundancer280]

Can you add throttle and bring the RPM's back up? Or are you already at WOT?

Once I lose power, I’ll push full throttle and the rpm on the left engine won’t go up, even at WOT

 

[Casty]

Did you ever get this figured out?