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Best Cruising RPM for SD2400 with Merc 350mag with Bravo3

PegasusA300 Member Posts: 6
Hi All!
I know this subject has been written about but I can't find the post I'm looking for.
I have a 2014 SD2400 I/O Mercruiser 350 Mag with a Bravo 3 drive.
I'm looking the best cruising speed RPM for fuel burn in GPH (fuel flow)….speed vs burn…all else being equal, properly trimmed…etc. I have the numbers for the engine itself…but that doesn't take into consideration the size of the boat…just engine. Same engine on a different boat might go faster on a smaller boat, slower on a larger boat. 
Has anyone installed a fuel flow meter on this boat and done the analysis best rpm for best speed vs fuel burn?
One of our favorite restaurants is about 1+45 away and if the fuel burn/mph is more efficient at a slightly different rpm then its a no brainer. I've been running between 3000-3300-3500 rpm but just can't tell the difference without a fuel flow gage. Any SD2400 owners played with the numbers and settled in on a good cruise rpm?? THANKS!!!


  • cjjjdeck
    cjjjdeck Member, Moderator Posts: 1,872 ✭✭✭✭
    Hopefully someone with a fuel monitor will respond.  In the meantime, I looked at some performance reports on the Mercrusier website with some similar boats as yours (well as close as you can get).  The best GPH ratings all seem to occur in the 3000-3400 RPM range of the 350 Mag.  Most of those boats tested have a higher angle of deadrise than your boat.  That means your boat should be planing at a lower speed which might adjust the RPM's down a bit for your boat.

    Although my boat doesn't have a fuel monitor (it is on my wishlist), with the 5.0 (same block as the 350 Mag, just shorter stroke) and the Bravo3, without question my boat is in a very happy place sitting right around that 3,000 RPM range.

    Here's the link to the performance tests:

    2012 SD237 I/O Mercruiser 5.0L MPI ECT/ Bravo 3
    2012 Load Rite Elite Tandem axle trailer

  • PegasusA300
    PegasusA300 Member Posts: 6
    Thank You!!
    I saw the engine data, but like you said…it changes with different hulls etc.
    I know there is someone out there that has that "need to know" gene in their DNA!
    Thanks again and I'll take a peek at the link you provided!