4500 rpm, 35 mph only...

[tayznild]

what is wrong? 14.25 x 21 prop.
it rev easy to 4500.
with 15 x 17 prop 30mph.
does i need a 4 wing prop?
15 x 25 is the answer?
any advise apreciated....

 

[Lyle29464]

Re: 4500 rpm, 35 mph only...

Need all info on your boat and motor and history. brands HP. How long is it? weight. Did you just buy it.

 

[tayznild]

Re: 4500 rpm, 35 mph only...

2000 4.3 engine on a 205 four winns. but it rev easy, i think it has good power engine. what is the biggest prop i can put on it. sx-m 1.89 drive..

 

[scipper77]

Re: 4500 rpm, 35 mph only...

If 4500 rpms is the max that the motor is rated for and you are hitting it at full throttle then you are set up correctly. If you are saying that you hit 4500 rpms and there is still plenty of throttle left then you need a different prop.

 

[rrhodes]

Re: 4500 rpm, 35 mph only...

Your prop should allow you to get as close but not over your recommended wide open throttle rpm max. Assuming your motor has a max rpm recommended rpm of 4500... Let us know the following..

What rpms are you reaching when you run wide open? Are you hitting a limiter?

 

[tayznild]

Re: 4500 rpm, 35 mph only...

The engine dies at 4700. So i think i need a bigger prop or change the drive ratio. Right or wrong?

 

[steelespike]

Re: 4500 rpm, 35 mph only...

WE need to slow down half a step.there are 3 4.3 motors 190 hp 1.81 ratio,205 hp 1.62
and 210 hp 1.62.all rated at 4,800 rpm.It needs to be prop to run at or near the 4,800.
You can't just put on a "bigger" prop,you all ready appear to be 300 rpm short and increasing pitch reduces rpm "about" 200 rpm per inch.You could have a number of things going on motor is not making full power and the tach isn't accurate.If the tach is accurate I feel the 17 should be over reving.So the motor still isn't making power.Numbers don't add up.
Varify the tach, If it checks out check the motor.Could be as simple as the throttle not opening all the way. Is a 205 Four winns hp or model?