Prop size / Pitch

[DuPont Spinner]

Howdy everyone. I would be very thankful for some responses to this post. I have a 1996 Suzuki 9.9hp two stroke with the original prop. The motor is in superior condition in all respects. The existing prop has three blades and is 10x6.5. The motor is mounted on a 13ft. fiberglass, dual hull, run-about style boat and doesn't quite get up on a plane. (Getting up on a plane might be asking a bit much from this motor.) However, I noticed in the owners manual that a 9x9 prop is also available. Would this size prop help me "get it up"? Some of the other sizes available are 9x7 and 9x8. Like I stated earlier, any suggestions will be very welcome. One more question: Do I have to use a Suzuki prop or will an aftermarket prop work just as well?<br /><br />DuPont

 

[ob]

Re: Prop size / Pitch

Does the engine seem to be generating high rpms and the speed isn't enough to get the boat on plane or does the engine seem to bog when trying to get boat on plane?If it tends to bog a steeper prop pitch will just make things worse.if ,however you are generating good rpms and the prop is not steep enough a prop changeout may be the ticket.<br /><br />Main thing you need to know is what rpms the engine will generate at WOT trying to get your boat on plane.<br /><br />Also insure that the motor is not mounted too low on transom.Anti ventilation plate of lower unit,just above the prop,should be roughly even with bottom of boat at transom.

 

[DuPont Spinner]

Re: Prop size / Pitch

Thanks Ob for responding. The cavitation plate is about 1 inch below the transom hull. I don't know what the rpm's are but the motor sounds as if it is completely wound out. At this point the boat is just on the verge of planeing and is not bogging down.<br /><br />DuPont

 

[ob]

Re: Prop size / Pitch

If possible try to get the motor a bit higher on tansom.Without seeing boat and judging by your description I'm guessing that a 9 X 8 or 9 X 9 prop may get the boat up on plane.A good prop shop should be willing to let you trial a prop before you decide on a purchase to see if it will alleviate your problem.