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.
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.
What is the prop pitch and height of the motor? Also is the lower a low water pick up unit?
I'm using trophy 4 blade 26 and 27 p. Sport master. Half inch below pad.
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.
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.
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.
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
Xtb21
Allison XB21 2+2 with Mercury 300R