Maxing out rpms 250 SHO

[lunker56]

I have a 2019 250 SHO on the back of a 2007 Ranger z21. I normally go from my normal 25p Yamaha T1 prop to a 24 P Tempest in the hot water/weather. I did that and I hit my max rpms with still throttle left. I went back to the 25P Yammy prop and same thing happened. Seems odd that I never hit 6000 rpms before and now I can hit before I get to max speed?

Any ideas?

[yam911]

Weather (temperature, pressure, humidity), boat load (weight and center of gravity), engine trim angle, engine mounting height, etc.. can all affect WOT RPM.

Other than that, I am out of ideas as to why you are seeing what you are seeing.

[lunker56]

Me too--nothing has changed as far as engine height or trim--I have a hydro jackplate. Very weird

[skeeter21ohio]

Speeds still close to the same?

[lunker56]

speed at max rpms is about 4 mph slower.

[samck96]

speed at max rpms is about 4 mph slower.

It sounds like you are having more prop slip. Check for anything unusual on the props, on the pad, lower unit.

[skeeter21ohio]

Is it a solid hub prop ?

[Wackyjig]

How are you getting your rpms? Smart gauge or analog? Is the limiter kicking in or are you limiting the rpm to 6k manually?

[lunker56]

Yes--it is a yamaha T1

[lunker56]

smart gauge--through Lowrance. Usually in hot water and weather it is harder to hit max rpms. Not easier. I am putting the third prop on this weekend to try

[skennedy]

If your using a gauge for jack plate height most likely the gauge is not reading correctly and you are running to high . I have always owned hydro jack plates and after a few years the gauge will get off . So I have learned to Mark the jack plate as to where I run most of th3 time so I know I’m close then fine tune on the fly .

[lunker56]

good idea--I will try that