Prop Size help

[arielalpuin]

Hi guys I just bought my first boat and would appreciate some help.

Boat: 1992 23.8' ProLine center console.
Engine: 2003 Yamaha 200 HPDI. Two Stroke

here's what i think is a problem.

I dont feel like the boat is running as fast as it should. With the throttle half way the boat is great, but from half way to full open throttle it doesnt feel like the boat goes any faster, the engine spins faster but i dont feel any advance in the speed.

I did some research and i think my prop is too small but i am not sure. My prop size is
14 x 17.
any help would be appreciated, if you guys need pictures of the engine i would be more then happy to post some. Thank you !!

[almetelo]

What is RPM's/REV's at WOT with usully load (people, fuel, gear, etc..)?

[TownsendsFJR1300]

The rubber insert (HUB) in the prop (for impact resistance), can be worn and slip .

Its usually more obvious strarting from a stop and nailing the throttle. If really bad, the engine will rev and the boat won't accelerate as it should..

Any Prop shop can put in a new hub and its not terribly expensive..

Here's a link to get a ball park on the size needed:

http://www.yamahaoutboards.com/owner...ance-bulletins

[arielalpuin]

What is RPM's/REV's at WOT with usully load (people, fuel, gear, etc..)?

Im embarrassed to say that i dont know, i didnt pay attention to that while in WOT. The most i saw the gauge mark was 4800 rpms. but i dont think i was at WOT.

I feel that when i go from half 3/4 of the way to WOT i dont feel a different in power or speed but only hear the engine go faster. I was also thinking if the engine is to high or something. but i am hoping its just the prop. Im thinking 14 x 17 is too small? >.<

[arielalpuin]

The rubber insert (HUB) in the prop (for impact resistance), can be worn and slip .

Its usually more obvious strarting from a stop and nailing the throttle. If really bad, the engine will rev and the boat won't accelerate as it should..

Any Prop shop can put in a new hub and its not terribly expensive..

Thank you for this information i was not aware of that. I will look into it. Is the rubber insert in the prop itself?

[TownsendsFJR1300]

Thank you for this information i was not aware of that. I will look into it. Is the rubber insert in the prop itself?

Yepper.

Pull the prop nut, the prop should slide off. The rubber hub is pressed inside. Just bring that down to the prop repair shop and they'll replace the innerds. When re-assembling, use a good marine grease on the splines.

If its wobbling, its a sign its worn, if the engine is in gear (NOT RUNNING), try turning the prop by hand. If its really bad, it will (and shouldn't), (pull the top cowl and make sure the engine isn't turning).

You should see close to 6,000 RPM's wide open, trimmed out for max speed. Likely in the low to mid 40's (MPH).


For a general idea, my 21' CC, with a F150, 3500 RPMs is about 25 MPH, 4,000RPM's about 30 MPH, WOT(6,000), about 46 MPH..

[countrytn]

you cant go by how it sounds or feels, look up your motor to see rpm operating range, check your boat at wot to see what the rpms are, if its turning too many rpms the prop number will go up, I would check rpms and contact a prop shop, be careful you can spend tons of money and get no improvement