df9.9 will not rev up in gear

[jbister]

I recently bought a df9.9 used. It runs great except it feels like it will not rev up in gear. I have had it on the water many, many times. It always starts with one pull, runs and idles great. While I do not rev it up in neutral, when in gear it feels like it should rev up a lot more. I do not have a tach but I have built a few small block chevy's and can tell when and engine is at high rpm vs middle of the road. When in gear, once I roll the throttle slightly passed the "choke" position for starting, the engine does not rev up any further. In other words, 1/2 throttle and full throttle are the same; there is not change in rpm.

I know that there is an over-revolution caution system and I am wondering if possibly something is preventing it from turning off or resetting. There are no warning lights on while operating the motor. Other than it feeling like it should have a lot more rpm left, it runs great!

[Hoosmatroos]

That is hard to tell from a distance. The motor / prop combination for your boat can be wrong. These motors are almost bullet proof. Only fuel hoses are known to crack and starter relays fail.