Re: prop help
Im sure the mods will move this to the prop section, but until then, what is your WOT RPM?
The best propeller size for your boat and engine combination is based on the recommended operating range at wide open throttle (WOT) for your engine, which you will find in your operator's manual. This will be expressed in terms of a certain horsepower at a certain RPM (revolutions per minute).
The goal in prop selection is to determine what propeller style and size will maximize performance for your boat, while allowing your engine to operate in the recommended RPM range. The correct propeller will prevent the engine from over-revving, yet allow it to reach the minimum RPM where maximum horsepower is produced.
Once your wide open throttle RPM falls within the recommended range of the engine manufacturer, you have a propeller that is suited correctly for your boat with respect to RPM. This is imperative, for the well being of your motor.
The general rule of thumb for changing the prop to fall within the recommended RPM range is for every 1" of pitch size, the effect will be approximately 200 RPM. Increasing the pitch increment by 1" will result in approximately a 200 RPM drop.
That being said, you may need more than a single prop to accomodate all the boating activities that you enjoy, from wakeboarding, to fishing, to cruising, etc...
i have an evinrude 1990 xp 150 i fish a lot of local tourn. i think its a 15 spline . i have no idea about pitch what do you think would be the best prop dimensions for my engine. 18'9 javelin boat