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GM 6.2 diesels for Roamers

Discussion in 'Chris Craft Roamer Yacht' started by captdirk, Apr 18, 2009.

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  1. captdirk

    captdirk New Member

    Joined:
    Apr 18, 2009
    Messages:
    6
    Location:
    San Francisco
    How are the engines working out for you, and did you ever work out the props? I'm going to try 17x16 props and 1.91 / 1.6 Velvet drives.
    Especially - how many gallons per hour do they burn? I got a couple 6.2s and am trying to size the fuel tanks. Are two 50 gals too small? I'm guessing about 5 GPH at full throttle, but can't get any real boating figures.
  2. John_C

    John_C New Member

    Joined:
    Sep 30, 2008
    Messages:
    16
    Location:
    St.Thomas, Ontario
    So far the engines are running great. I have not gone enough distance to give you an answer on consumption,but will let you know as I figure it out. My boat has two new 75 gallon tanks in it. I have made changes to the fuel filters etc to make sure I am getting any moisture out, and a good flow. I do believe I am going to have to change the props though, the boat is lagging, like a boat that does not want to come up on plane, and if I push the issue,the engines start to rev out, and the boat does not move. At first I was worried I had a transmission problem, but I have had both engines do it, so I believe its a prop problem. Can anyone recommend a good company to contact, who could advise me on size and pitch?
  3. chesapeake46

    chesapeake46 Senior Member

    Joined:
    Jul 26, 2009
    Messages:
    1,500
    Location:
    Chesapeake Bay, Delaware Bay & S.Jersey
    I got this information off of a great forum.... err ah, here in fact.

    http://www.boatfix.com/how/props.html
  4. John_C

    John_C New Member

    Joined:
    Sep 30, 2008
    Messages:
    16
    Location:
    St.Thomas, Ontario
    Great link chesapeake46,that is some good basic knowledge I really needed to read. I am having a slipping problem,and I have a couple things I need to try. Thanks for the prompt and good reply.
  5. chesapeake46

    chesapeake46 Senior Member

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    Jul 26, 2009
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    1,500
    Location:
    Chesapeake Bay, Delaware Bay & S.Jersey
    Your welcome but the credit goes to either Marmot or K1W1 who passed it on here a while ago.
    I just pasted it into my favorites.......:eek:
  6. yotphix

    yotphix New Member

    Joined:
    Jan 5, 2007
    Messages:
    97
    Location:
    Southern California
    Thanks for that, I hadn't heard that before and this topic has been discussed many time on the web and around the table. As a side note, it is a very bad idea to turn Outboards inwards. Not having rudders, (or at least, having only inefficient rudders, on the wrong side of the prop) they have none of the benefits you describe. I have had to drive a 32' Jupiter CC rigged this way and it is intensely frustrating. As I am sure everyone knows, the "normal" or outboard rotation at the top has the advantage of walking the boat in the same direction as spinning it (thanks to the one fwd, one rev thrust). That is what most captains like about it. On the little Jupiter, the two forces cancelled each other out. When I asked the factory why they rigged it that way they claimed a better holeshot, which is not exactly of prime importance on a CC fishing skiff/yacht tender.
    The only way to drive it is to treat it as a single, and a very heavy steering one at that.
  7. Laurence

    Laurence Senior Member

    Joined:
    Aug 30, 2006
    Messages:
    250
    Location:
    Chattanooga TN
    6.5 AM General Diesel

    HiPerformer says this diesel will be be available late August.