RPM question

Discussion in 'Boating Discussion' started by El_Guapo, Mar 14, 2010.

  1. El_Guapo

    El_Guapo Newbie

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    El Guapo
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    I have 150hp Yamaha 2 stroke . Manual says WOT 5500 max. Today I try run WOT , the digital gauge read 5600 rpm. Is extra 100 rpm make any damage to the motor?
     
  2. LTBOLTMAN

    LTBOLTMAN Team Tail Chasers

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    Leoman
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    you toasted your motor dude
     
  3. LTBOLTMAN

    LTBOLTMAN Team Tail Chasers

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    I kid I kid....I would follow the manufacturers recommendations tho
     
  4. Slater

    Slater cuss on Monday,pray on Sunday,dream about one day

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    How was the boat loaded? Full of fuel & gear or empty? Rpms should drop if loaded with weight some, thats why ask if you were running light. Did you trim up the motor to get that range? Rpms will increase & engine becomes more efficient as its trimmed out to the sweet spot..
    I dont think 100 rpm is going to matter but might want to talk to props of san diego, tell them your size / pitch & application & they will tell you if she's proped correctly.
     
    Last edited: Mar 14, 2010
  5. El_Guapo

    El_Guapo Newbie

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    I have 21ft Center console. with 80gallons fuel. I was by myself, no gear with 25 gallon of livewell. I trim the motor up until prop just came out of water.
     
  6. meddo63

    meddo63 Newbie

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    mark
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    Test it with the load your going to run. Then check the RPM's against your speed. When you trim it up (not out of the water), and when you just start to loose speed. Trim it back down a hair and see what your RPM's are
     
  7. ShadBurke

    ShadBurke I've posted enough I should edit this section

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    Shad Burke
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    I use to get about a 300 RPM difference between full load and light load conditions. In addition, depending on motor trim, I could get an additional 400 RPM variance. Yamaha recommended full throttle RPM for my 225 4 strokes was between 5000-6000 and given the variances above, I would usually be in the 5400-6100 RPM range.

    I sold that boat with 1,000 hours and never had any issues resulting from over-revs. Not sure on the older 2 strokes but my 4 stroke did have a rev limiter that i believe restricted RPMs above 6300.
     
  8. furniture 4 me

    furniture 4 me Well-Known "Member"

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    your tack could be off a little, the computer in that motor, or rev limiter will not allow it to over rev. it starts to buzz or die out a little. i have the same outboard, you shouldn't be able to get it to 5500 fully loaded if your propped correctly according to what the Yamaha guy told me. by the way 100 rpms over is OK once in a while.

    Also be carefull how high you trim that thing out, you can start to suck air and burn the impeller up.
     
  9. MATTANZA

    MATTANZA old man of the sea, in training.

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    RICK
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    most motors have a governor that keeps the motor from over-reving
     
  10. El_Guapo

    El_Guapo Newbie

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    Thanks you for all your input.
     
  11. sickcat

    sickcat Silverback

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    Kerry
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    100 RPM over is not a problem. Much better to be a little over than under. Especially if you fish with 1 or 2 more people your propped about perfect - unless your getting that WOT RPM by bringing the prop too far out of the water and cavitating it. The 5500 max in your manual is the RPM you need to make @ WOT with the boat loaded as you run most of the time.

    Check it again trimming it as meddo63 suggests. If you still get 5600 your fine.
     

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