Poor Performance

I have a 2000 Johnson 175 Fastrike carborated Model # RJ175PLSSC.
At this point I am running 49.9mph(GPS) @ 5400 RPM.
Ampiant Temp. 93 degrees above average humidity
-Currently running a 14 1/2 X 26P Raker Prop
-When running 14 1/2 X 24P Raker speed same but RPMs at 6500 RPMS
-Check and measured Prop to Padis 4.5"
-fuel used in last 4 gas tanks fills is 5% Ethanol.
-I have run engine tuner throught engine
-Replaced spark plugs
-Replace Power Pack
-Technician checked compression to be good
-Engine starts and idles fine very seldom spits
-Replaced VRO
-New Lower Unit 1.86:1 gear set
-Approx. 450lb load on boat at test run.
When I first ran this Boat / Motor New in Jan. 2000 speeds were just at 64 mph and I do not remember the rpms.
Question I have is I have been told that I should be getting more performance out of a 175hp motor

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At this point I am running 49.9mph(GPS) @ 5400 RPM.

-Currently running a 14 1/2 X 26P Raker Prop

When I first ran this Boat / Motor New in Jan. 2000 speeds were just at 64 mph and I do not remember the rpms.
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Using a prop speed calculator - 5400 rpm with a 26P prop and 10% slippage equates to about 64 mph.

That means one or more of your measurements are inaccurate - whether it is your prop, gps, or tach

+1 to what Seahorse says. I don't see a 1,100 RPM difference between a 24 and a 26 P Raker. I know speedo's are inacurate but what does it register? What is your water pressure at wide open throttle? Two other things comes to mind 4.5" below pad is too low on your transom starting point for that Stratos is 3.5" below pad. And the other thing is if you have a Lowrance GPS you could perform a hard reset on the unit. Just remove you chip before doing the reset.

Fred, To be honest I feel like the boat is running just about as good as it did when I first got it New in 2000. I have done these checks concerning speed but as far as really doing any tweeking of the settings like prop to Pad. I was informed that using the Raker Props that a 3.5" Pto P measurment might suck air. I am going to have a friend in his boat run with me to see just what he is running and then I will have him to compare to speed wise.

That is what I have been told also but I made certain that what I saw on my guages is what i said. I know the accuracy of the Speedo is not the gospel and i used a hand held GPS. I will get a friend with a newer boat to pace me running the lake and see what he gets as my speeds on his Gps unit on his boat.