I would make sure it's set up correctly before you go spending money. Which boat is it? If it's the ZX boat it has a setback plate and setup will be much easier. These will be some of the pertinent questions to start with.
What are your rpm's at max speed on it?
Do you know how to measure prop height? If so, what is it?
Is the prop damaged or dinged in any way?
What is top end speed?
What kind of load are you carrying?
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