RPM's too low

I have a mercruiser 3.0 145hp engine on my 2005 bayliner 195 cl with an alpha 1 outdrive we are currently getting only 3600-3700 rpm at top speed and only going about 32 mph and everything i read it says the rpm's should be 4400-4800 and going atleast 40 mph. Is it hurting the motor going in the lower rpms and what do I need to do to get the rpm's up?

Thanks
Scott

Re: RPM's too low

List of possible causes of low WOT (Wide Open Throttle) rpm.

In no particular order

Engine Won't Reach Operating RPM. Check

1. Fuel condition. Type and Octane possibly old fuel
2. Propeller pitch or diameter, damaged blades
3. Restricted fuel pickup tube or anti siphon valve Fuel System Test
4. Crankcase oil volume, high oil level can cause aerated oil and lifter collapse
5. Marine growth on hull and outdrive
6. Wrong gear ratio in outdrive
7. Restricted carburetor air intake (clogged flame arrestor)
8. Restricted exhaust system (broken exhaust shutters/flappers) in engine transom shield or drive
9. Poor cylinder compression Compression Test
10. Carburetor defective, or wrong type.
11. Fuel pump pressure and vacuum
12. Boat overloaded, improperly loaded, or improperly trimmed.
13. Engine Overheating
14. Engine timing and ignition system operation
15. Remote control cables and linkage for proper travel to open throttle plates fully.

Re: RPM's too low

I just went thru the same thing.My 3.0 litre would only hit 4100 rpm. I went from a 21 to a 19 prop and it made all the difference in the world for me .As of yesterday it actually hit 4600 for the first time and 42 mph and my holeshot for skiing is way better....Bob