props for 2003 366

[mysticskies]

I have a 2003 366 with twin Mercruiser 6.2s rated at 5000 rpm. However, the rpms top out at 4000 with the original 22 x 21 4 blade props. My mechanic suggests I change to a lower pitch and one prop company says I should use 22 x 16 in order to reach 5000 rpm. That's quite a change from the OEMs.

Does anyone have any opinions about this? The prop company would like to know the typical speed of the 366 with these engines running at 5000 rpm. Does anyone know the answer?

Thanks

[mjk1040]

Beware! What you wish to gain on the top end you'll lose on the bottom end. Mobility at idle in tight places. I'd suggest a call to carver with your HIN and find out what OEM is. Our 355 MY has increased pitch props to keep it from over rpming!

[Midnightsun]

Either your boat has gotten heavier which happens quite often due to accumulated junk and/or the possibility of water infiltration or the engines are getting weak or even just a slightly dirty hull. As you can see, there are several factors that can affect this.

The important part is the WOT of close to 5000 should be able to be achieved with normal typical load on board as this is the indication of how well the engine is coupled to the prop which is comparable in the automotive world to having the correct gear on the transmission. A few hundred rpm below the max is fine but 1000 indicates you are lugging the engine which will reduce the engine lifespan.

Has the boat ever performed close to 5,000 rpm at WOT since you got it?

[bud37]

Welcome to the forum......guessing by your location you are in salt water ???.....if so when you observed this 4000rpm number, was the bottom freshly cleaned, as this will greatly affect the rpm as has been already mentioned ( something to consider ). Your prop guys will know this, sorry can't help with the oem props.......