Just checked my fuel economy on my xb2003 with a 1995 225 promax efi. The lake was rough about half the time I was running and I would be turning 4000 rpm's at 40 mph. The rest of the time it would be 60-65 mph at 5000 rpm's. It got 2.9 mpg, not what I was hoping for but not entirely accurate neither. The rough water and idle time in and out of the dock brought the number down. Can't wait to see what it gets with better lake conditions.
A promax an old style very powerful thirsty motor. 3 mph is not bad for that engine in the described conditions.. You will need an opti to get 5+ mph at cruise.
Last edited by xb03fs; 08-01-2017 at 09:23 AM.
I've been averaging a hair over 4 with my Promax.
1995 Allison XB-2003 225 Super Mag. It's slow and I'm ok with that.
Haven't checked mine with the 225 Pro XS but, it does extremely well. I am pretty sure I can travel as far on a half a tank it took almost a full tank to do before. I ran from doctors lake on the St. Johns to Julington creek then, down past the Shand's bridge on the way back went all the way to redneck beach in Black Creek then back to the ramp in Doctors lake and I burned a less than half a tank of gas. I am guessing that is between 50-60 miles and around 10 gallons of fuel. I ran above 70 for some of the ride. In Black creek I came off plane and on plane around a dozen times.
If the SmartCraft gallons per hour read out is accurate my 03/225X can getover 6 mpg at lower speeds. With a 28 ProET I recorded 6gph at 41 mph, 7gph at 48 mph and 10gph at 60 mph. After that it drops off fast. My Trophy, ProMax and Q4-OT props were also pretty good but couldn't match those numbers.
I'm guessing the best fuel economy comes from the highest speed with the lowest rpm's? Keeping the boat somewhat "aired out" gives the best fuel economy?
My xb2003 with a 225pm average was 4.1mpg, with a 280 3.5mpg under 6k rpms lol.
Xb2003 - 300xs
100+ mph club
My old 2.5 Carbed XR6 is soooo thirsty.....yet so reliable.
22R
Allison XB2002 / Merc 150 XR6
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