RT188 Help.

[dpart12]

All,

So I just had my 2014 RT188 replaced under warranty. I now have a 2019 RT w/ my old 2014 Mercury Optimax 115 hp. I took it out for the first time today and could not get max RPM’s or speed. I have a brandnew Spitfire X7 SS prop 21 pitch, i should be getting 5800 to 6000 rpms at 45-48 mph. Never got faster than 33 mph. My hole shot was slow, also when i engage the throttle and putting it in gear, i am not getting any power till i get half way down to open it up. There is something definitly wrong here. In the old boat, i had an aluminum 4 blade 22 pitch prop and was easily going 44mph @ 5600rpms with an excellent hole shot. Any ideas what it might be?

[jc1992]

Check the throttle cable.

[GeauxTide]

Other than the possible cable issue, a 21 is tool tall. I'm turning 5600 with my 19 at Hole #2.

[Lowerider58]

Also check to see if they mounted the motor the same height on the transom. I agree that the prop should be a 19" if you're going to run a 4 blade.
Was the new boat set up at the Ranger factory or a dealer?