Mounting height for Outboard Jet?

Discussion in 'Propulsion' started by BertJet, Apr 16, 2005.

  1. BertJet
    Joined: Apr 2005
    Posts: 2
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Canada, Alberta

    BertJet New Member

    I am mounting a 40HP Merc JET on a 16" Crestliner Modified V-Hull jon boat.
    I must decide on the proper height to mount it and just cannot decide.
    Too high and I may encounter cavitation (air sucked into the impeller), and too low may decrease top speed, cause more splashing and increase the risk of hitting rocks.
    Any body has experience with this kind of issue and can give me advice on the proper height? (My gage is the front of the intake compared to the absolute bottom of the boat).
    :(
     
    BertJet, Apr 16, 2005
    #1
  2. Arrowmarine
    Joined: Jul 2004
    Posts: 107
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Southern Oregon

    Arrowmarine Senior Member

    I want to say that we always put them with the leading edge about 1/4" above bottom of hull. Dont quote me tho
     
    Arrowmarine, Apr 16, 2005
    #2
  3. BertJet
    Joined: Apr 2005
    Posts: 2
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Canada, Alberta

    BertJet New Member

    Thanks! It kindda confirm what I have heard. I was told by another user to mount the front of the intake flush with the boat bottom. One Merc dealer told me 1 inch below!
    Have you had cavitation problem in choppy water?
     
    BertJet, Apr 16, 2005
    #3
  4. Arrowmarine
    Joined: Jul 2004
    Posts: 107
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Southern Oregon

    Arrowmarine Senior Member

    Sometimes in tight turns
     
    Arrowmarine, Apr 16, 2005
    #4

  6. cyclops
    Joined: Feb 2005
    Posts: 1,059
    Likes: 5, Points: 0, Legacy Rep: 38
    Location: usa

    cyclops Senior Member

    On the Delaware River the trends vary. BUUT. VERY small stone bottoms normally UP 1-2" or you drop anchor and do a clean out by going in to the water. Rock and mud, anything goes. Old weed beds are death to all jets here. The weed stems are pinky finger diameters. This from 5 years back in time. New pumps may eat anything by now.
     
    cyclops, Apr 16, 2005
    #5
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.