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What RPM do you cruise at?

familytraditionfamilytradition Member Posts: 2 ✭
in Rinker Express Cruisers Forum
I purchased a 2005 360 last year. I have been cruising at 3800 to 3900 RPM which is roughly 21 knots. The boat runs great and gets on plane and stays on plane. I recently had my mechanic on board and he told me to run the boat at 3600. My engines are Mercruisier MX 6.2.

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    LaReaLaRea Member, Moderator Posts: 7,555 mod
    Same for me -- 3800 to 3900 rpm on my 370 with 496s.  Why did he say 3600?  Is there some problem with your engines?  

    If you slow down to 20 kts, won't your boat be making a huge wake and sucking down enormous amounts of fuel?  Most Rinker cruisers get their best fuel economy around 25-28 kts.  

    Also, if you have sterndrives, 21 kts (24 mph) is very slow for that engine speed.  At 3900 rpm, my previous boat (342 with Merc 5.7) would do 26 kts (30 mph), and my 370 does 28 kts (33 mph).  Maybe you need different props.

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    Black_DiamondBlack_Diamond Member Posts: 5,439 ✭✭✭✭✭
    I cruise at 3800-4200 rpm @ 26/27 knots. Bravo-III 22P, 350MAG MPI. 2003 342. 

    Past owner of a 2003 342FV
    PC BYC, Holland, MI
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    Dream_InnDream_Inn Member, Moderator Posts: 7,561 mod
    I think most Rinker boats cruise better at a little higher speed, hence higher RPMs.  My 400 runs in the same ballpark as BD at 3800-4000 at 26-28kts.  B-II with 496s.

    Dream 'Inn III -- 2008 400 Express

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    familytraditionfamilytradition Member Posts: 2 ✭
    Thanks for the feedback. 

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    pault1216pault1216 Member Posts: 206 ✭✭✭
    edited July 2016
    I always cruised where I thought I got the best fuel consumption and also noted that most other small block V-8s were often at 3500rpm for best fuel economy (with correct props).
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    TonyWalkerTonyWalker Member Posts: 744 ✭✭✭
    Salt Shaker seems to enjoy 3600 rpms which gives us about 26 mph or roughly 22.6 knots.
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    summerxsummerx Member Posts: 211 ✭✭✭
    my 310 with merc 5.0s seems to like about 3600 rpm.  engines have that smooth sound at that point.
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    LaReaLaRea Member, Moderator Posts: 7,555 mod
    With most Rinker express cruisers, the "sweet spot" of cruise speeds is relatively wide.  You can cruise almost any speed you want (within reason) and the fuel economy (miles per gallon) doesn't change much.

    For example, Boattest.com tested a 2005 360 with the Volvo 320-HP package.  The most efficient cruise speed was 28 knots.  But the boat could cruise anywhere between 24 and 30 knots without losing more than 5% in fuel economy.  Even at 32 knots, it was only losing 10%.  

    On a 342 with Merc 6.2, it could go anywhere from 25 to 35 knots without losing more than 5%.
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