Low speed trolling with large Horsepower Motors

Discussion in 'Propulsion' started by Barry, Jan 9, 2019.

  1. Barry
    Joined: Mar 2002
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    Barry Senior Member

    There has been an increase of the use of twin high horsepower engines for trolling. Many boats use just one of the single HO motors for low speed/rpm trolling and on others they will have a smaller trolling motor.

    Certainly if you use a cheaper low hp engine, you don't run the engine hours up on the more expensive HO motors.
    My question then is this: With the new multiport direct injection engines, are there any issues with running these engines at lower rpm, say 600 rpm for extended periods of time?
     
  2. JamesG123
    Joined: Mar 2015
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    Location: Columbus, GA

    JamesG123 Senior Member

    Probably not if the EFI brain box is smart enough to keep mixture right to avoid fouling. Another concern might be if the oil pump isn't turning fast enough to maintain the spec main bearing oil pressures.
     
  3. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    What engines are we talking about here ?
     
  4. Barry
    Joined: Mar 2002
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    Barry Senior Member

    Sorry brain failure here
    300 hp Yamaha
     
  5. Mr Efficiency
    Joined: Oct 2010
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    Location: Australia

    Mr Efficiency Senior Member

    I'd be rather surprised if there were adverse effects on the engine. After all, the manufacturers know this will be a common use of the engines. A boat shop that sells and services them will know best. But I can't imagine what problem could arise, even with the old smokies there were not too many dramas from extended slow speed operation, once CD ignition became the norm.
     

  6. tpenfield
    Joined: Dec 2016
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    Location: Cape Cod, MA

    tpenfield Junior Member

    Are you asking about multiport injection or direct injection? Either way, running at idling speeds for long durations is not really something to worry about. There may be a bit of carbon build-up, but figure if someone is out fishing for 3-4 hours, they will probably 'haul buckets' getting back to the harbor and that will make it all good. :)
     
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