How many RPM's should I achieve (Ideally / average) with a 2000 - 150 Mercury HP on a 21 foot bay boat.?

Question

I know that it is dependent on the load / wind / water / prop ect.. but I would like to know based on an average. Currently my top end is around 4600.

Answer 1

that seems about right for a two stroke... check a SELOC manual at your local library to be sure. you didn't mention if it was a direct injection, four stroke, or 2 stroke - you need to know that.

Answer 2

We really need more information to give you the best answer.  I'll do my best with what you have here.

Ideally you should be able to reach just shy of your redline with a light load when running in conditions that is typical for you.  If we are talking about a 2stroke merc 150 hp outboard circa 2000, then you should be able to turn the engine at about 5500.  

If you are looking to reprop the boat, then do yourself a huge favor. Make sure the engine turns at the rpms that it should before you start playing around with pitch and diameter sizes. Too many times, boat-owners will go out and buy a new prop trying to get some more top-end only to find out later that the engine wasn't making the right power because the engine under no load couldn't reach the proper redline.

If you want a better and more complete answer, then please give us more info about what type of motor it is and what you are looking to accomplish.  I am sure I can answer whatever boating question you have if I have the right info to start with.  Good luck I hope this helps!