Results 1 to 9 of 9
  1. #1
    Member
    Join Date
    Aug 2021
    Location
    Lebanon, TN
    Posts
    4

    Need help . Allison xtb setup with 14 inch jackplate.

    I can only get 74 mph out of an allison xtb w 14 inch jack plate running a 225 promax . Any help would be greatly appreciated.

  2. Member
    Join Date
    Feb 2006
    Location
    Tazewell Tn.
    Posts
    2,614
    #2
    What is the prop pitch and height of the motor? Also is the lower a low water pick up unit?

  3. Member
    Join Date
    Aug 2021
    Location
    Lebanon, TN
    Posts
    4
    #3
    I'm using trophy 4 blade 26 and 27 p. Sport master. Half inch below pad.

  4. Member
    Join Date
    Sep 2010
    Location
    St Clair Shores, Michigan
    Posts
    7,591
    #4
    I'm not an Allison expert, but I suspect that is the wrong prop for this combo. The experts will get ya headed in the right direction.

  5. Member
    Join Date
    Jan 2013
    Location
    knoxville tn
    Posts
    257
    #5
    Trophy will run good. Raise your engine to where lower cone even with the Pad. If you want raise just above a little. Work ok also.

  6. Member
    Join Date
    Feb 2006
    Location
    Tazewell Tn.
    Posts
    2,614
    #6
    Every boat is different. You should have about a 12.5" pad on your boat, I have a 10.5" pad on my xb2003. Go back and read my thread about my xb2003/225 promax, I talked about my boat with a 9" plate and four different trophy props and then on to a 14" plate with the same props. My boat really came alive on top end when I went to a 14" plate and raised the motor from 1/4" below pad to 1/2" above pad. My latest top speed is 88.5 mph, which I'm sure I'll top this fall or winter. I expect to get into the 90's.

  7. Member Dark Allison's Avatar
    Join Date
    Jun 2004
    Location
    Versailles,Ky
    Posts
    762
    #7
    That boat should run over 90 all day long. Mine liked Performers and the txp 4 blade props. I ran 1/4” above pad. What year is the boat? The 94-96 had more built in setback. Are you hitting the rev limiter with your current prop?
    Allison XB21 2+2 with Mercury 300R


  8. Member
    Join Date
    Feb 2006
    Location
    Tazewell Tn.
    Posts
    2,614
    #8
    Quote Originally Posted by Dark Allison View Post
    That boat should run over 90 all day long. Mine liked Performers and the txp 4 blade props. I ran 1/4” above pad. What year is the boat? The 94-96 had more built in setback. Are you hitting the rev limiter with your current prop?
    Which boat are you asking about, my xb2003 or Mike's xtb21?

  9. Member Dark Allison's Avatar
    Join Date
    Jun 2004
    Location
    Versailles,Ky
    Posts
    762
    #9
    Xtb21
    Allison XB21 2+2 with Mercury 300R


Tags for this Thread