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  1. #1
    Join Date
    Feb 2011
    Location
    England
    Posts
    3
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    Mercury Sport Jet 2.5 L Conversion.

    I Have a Toasted 175 XR2 Sport Jet In a Regal 1700. The boat is in good condition Engine is Junk.
    2 Cylinders destroyed,
    4 Con Rods
    6 Pistons
    Crankshaft Gone.
    Hole in Crank Case.
    To name but a few problems.

    I'm In England so parts for these motors are none existant.

    A freind of mine who has a machine shop races NS2000-F2 Power boats with 2 litre XR2 2 stroke engines, tuned to 200 hp he's suggested using one of his engines and converting it to run on the jet pump.

    He's suggested machining the end of a standard merc drive shaft (8 spline) onto the end of the sport jet drive shaft (13 spline) to enable me to use the standard V6 crank rather than a replacement expensive sport jet crank.

    Question is has anyone ever tried this aproach ??

    The casting s on the 2.0 ltre race engine are almost identical to the 2.5 sport jet

  2. #2
    Join Date
    Aug 2007
    Location
    Ft. Lauderdale, Fl
    Posts
    7,954
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    If the weld is good, it should work just fine.....
    "One of the penalties for refusing to participate in politics is that you end up being governed by your inferiors". Plato .

  3. #3
    Join Date
    May 2009
    Location
    pacific
    Posts
    166
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    i puchased a used jet pump to use on my 200 merc the shaft was 5 inches to long i took the shaft out of the pump and to a local machie shop they cut off what i didt need put new splines on it and i havent had a single issue out of it

  4. #4
    Join Date
    Sep 2006
    Location
    Key Largo, Fl
    Posts
    2,505
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    Actually the jet crank is much less cost than the outboard one from mercury,although I agree they aren't as plentiful.I'm not convinced the 2.0 will have the torque required to turn the pump,a 2.0 making 200 hp is probably turning 7000-7500 to do it,that wont work on a jet pump to my knowledge,I don't know if smaller impellers are available,etc.Even if they are I don't think it would be good for a pleasure boat,i expect you would trash the pump and gearbox quickly,Chris

  5. #5
    Join Date
    May 2003
    Location
    Ft. Worth, Texas
    Posts
    1,052
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    The jet pump is limited to 5800-6200 R's with any motor, and I agree the 2.0 will be a disapointment on power compared to a 2.5...... been there, and the 175 makes more bottom end power than the 240 EFI, I proved it more than once.

    Kaase Outboard Hydro/Bottle Fed 300 Drag

  6. #6
    Join Date
    Feb 2011
    Location
    England
    Posts
    3
    Post Thanks / Like
    Thanks Guys,
    So basically the converted drive shaft shouldnt be a problem,

    But the feeling is the 2.0 ltre motor will have a lot less bottom end than the 2.5 sportjet even though it has been ported and tuned to 200HP.

  7. #7
    Join Date
    Sep 2006
    Location
    Key Largo, Fl
    Posts
    2,505
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    The porting and tuning is to increase hp by increasing rpm,not an option on your jet pump,you need torque that comes from the increased cubes in my opinion,Chris

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