921 how high you running the Mercury?

[rudapa]

Now that I have my 7 cylinder running on 8 cylinders, curious how high this motor needs to be? I've went as high as 4.25" on the Atlas Hyd plate and the water pressure stays at 14 to 15. Curious how high y'all run? I was doing a lot of trying things while my one plug wire wasn't fully attached. I didn't see any real difference from 3" to 4.25" (15 on the plate gauge). Trim on SC2000 gauges says 8.5. I'm still in the 10-hour break in so can't run it WOT much but I did get 72.5 at 6300 RPMs.

In case you were wondering, it performs much better on 8 cylinders.

[ssbassman]

Mine runs best at 9-10 on the atlas guage! I just don't see how guy's are running at 13-14

[Triton19x2]

On my Atlas the gauge setting of 13 is 3.25" below pad. Looking at the gauge sensor the part attached to the plate is all the way down with the screws in the very top of the slots. I'm running a 23 Fury 3 blade on a 721. I can run a 24P Temp+ at 14 on the gauge which measures out to 2.75" BP....just for comparison.
Different boat but it does matter where your gauge "pieces" are as far as what the gauge reads.

[opaleski]

2 TO 3 inches below so called "pad"