Outboard power loss at above 1/2 RPM

Discussion in 'Outboards' started by ryanonthebeach, Jun 25, 2009.

  1. ryanonthebeach
    Joined: Mar 2007
    Posts: 75
    Likes: 6, Points: 8, Legacy Rep: 61
    Location: CA

    ryanonthebeach Junior Member

    Hey

    I'm not sure if this is the right place to ask but I'm down in Mexico and itching to dive but my dinghy outboard has been acting up. It wouldn't run without the choke out so I took it in to have the carburetor cleaned and now it idols great but about at half RPM and the dinghy stops picking up speed and the engine just revs shoot up to full rpm, almost like she's slipped out of gear, or the propeller has lost it's grip on the water. She used to cruse at 18mph but can't even get her to half speed before the revs shoot up. I would take her back into the shop but explaining this in hand signs is a challenge. Would be good if I have some idea of what's wrong first but this has me confused.

    Your help would be appreciated.
     
  2. kenJ
    Joined: Jul 2005
    Posts: 349
    Likes: 5, Points: 0, Legacy Rep: 56
    Location: Williamsburg, VA

    kenJ Senior Member

    Many newer outboard have the prop attached to the drive shaft with rubber instead of using a shear pin. Check to make sure the prop isn't slipping. Did anything esle change? Same dinghy with same load? Are you mounting it the same way? Is the angle to the transom the same? The prop could be either cavitating or sucking air both of which will cause the rpms to rise and thrust to fall.
     
  3. ryanonthebeach
    Joined: Mar 2007
    Posts: 75
    Likes: 6, Points: 8, Legacy Rep: 61
    Location: CA

    ryanonthebeach Junior Member

    Spun hub

    Ken

    Besides cleaning the carb nothing else has changed. I think it may well be a spun hub as you suggest, Iam going down to the marina today to check that.

    Thanks
     
  4. ryanonthebeach
    Joined: Mar 2007
    Posts: 75
    Likes: 6, Points: 8, Legacy Rep: 61
    Location: CA

    ryanonthebeach Junior Member

    Spun hub

    Thanks Ken

    It was a spun hub... took the prop off and the rubber was all chewed up.
    Got to get a whole new prop!

    Thanks
    Ryan
    www.psychosnail.com
     

  5. Paul aka watertaxi
    Joined: Jun 2009
    Posts: 14
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: North East

    Paul aka watertaxi Junior Member

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