This. Although I know plenty of people that cruise 4000 - 4500 rpm all day and never think twice about it.

For me, it is just under where the secondaries open up :) So just under 3400.

+1. Although go-fast are kind of an odd duck cause the "cruise speed" could be pretty fast and not what most would consider cruising at all. Depends on the hull, and torque/hp curve on the engine.

So for my sea ray its 3100rpm cause thats where the manufacturer told me and it does get really good fuel consumption at that range, even though I prefer speeds closer to 2900-3000rpm for what I consider crusing. For my Apache I don't have a clue and will likely never know until you get some fuel burn readings to run the numbers with.

rule of thumb for a mpi engine take divide horse power by 12-12.5 and that gives you fuel burned in gallons per hour at wide open throttle.

6,250 gallons per hour seems reasonable for a 500hp engine.

I've always heard the same as this and that it comes between 3000 and 3500 rpm's depending on the motor and which carb it has.

See ya,
Kelly

The speed where the wife quits b****** about going too fast.
I agree with carburated motors just before the secondarys open and on injected motors about 3500

W.O.T. No really the Cig 38ts 525s seams to be about 3800 rpms The boat loosing up an fuel ecno seems right. Artie :whistle:

415hp / 12 = 34.58 gallons per hour X 2 = 69.16 gallons per hour twin 502's. Looks reasonable, but their carbed motors not mpi.

3,500