---

The SCD3 is only available in 13 inch diameter for your motor..
Again, we only have a choice of pitch with any given brand of prop.
http://www.ptpropeller.com/content-pr...amaha.html

You have a 16 pitch SCD3 prop.
Less pitch will give you more RPM's at WOT and usually slower top end speed but a faster hole shot.

More pitch will give you less RPM's at WOT and usually slower out of the hole but faster top end.

It sounds like you need less pitch, like an SCD3 15 pitch prop (maybe even a 14 pitch) which will increase your RPM's at WOT. As it is right now, you are at 5000 RPM and you should be 5300 to 6000 RPM's.

I would try the 14 pitch during your trials and trying different SCD3 props.

See the diameter of all the SCD3 props which is 13 inches.
Below is the SCD3 R14 pitch prop for Yamaha motors..