Using muffs on Yamaha four strokes

Discussion in 'Boating' started by Bigun, Jul 9, 2007.

  1. Bigun

    Bigun New Member

    Burnet, TX
    Had my 100 hp Yamaha four stroke in the shop today and the mechanic used the muffs to run water while testing it. He had used the hose connection two years ago when it was last in. He had told me that was the way to do it. I questioned him on it today and he said this was per the factory recommendations that they had changed their mind. I guess it is setteled the muffs are the correct way to go.
  2. Mr.T

    Mr.T Active Member

    The hose connection is for flushing the motor, not feeding it water while it's running. Use that connection and you bypass the water pump, which can quickly burn it up.

    The owner's manual is pretty clear on that point. It's surprising that the factory-trained technicians wouldn't have known better from the beginning.