[THEFERMANATOR]

Originally Posted by bgreene

Old fashioned method:
1. Fill the tank full.
2. Go for a measured boat ride at a given rpm- say 10 miles round trip.
3. Then re fill tank and see how many gallons it takes.

Then you'll know for sure, absolute.

The older 225 loopers gulp fuel when you put the hammer down.
If running under 4,000 rpm shouldnt be too bad. If run hard...... I'd guess 20_+ gallons per hr no problem.

Depends upon the year. The 86-87 engines were the best on fuel of the big loopers as they were a 2.7L engine with very aggressive porting. The 88-91 engines were the best all around with the 3.0L displacement, milder porting and idle reliefs which made them idle better and more reliable. The 93+ engines have the smallest ports and very restrictive exhaust in them. It makes for good off idle performance along with cleaner emissions. they had to add in finger ports though to get the HP back that was lost with the exhaust changes and also added in a higher flow tuner. Then around 99 or so they offerred the 250 which is a 225 with better porting i nthe exhaust I believe and the early style intake. The 93+ engines are by far the thirstiest of the big OMC loopers though due to the restrictive exhaust and the need for finger ports to compensate.

A stock 225 should burn around 23-25 GPH at WOT, and fuel burn drastically changes around 4,000RPM's. I know my ported and max bored 225 would gulp down an easy 28-29 GPH when I dropped the hammer on it, but burned 11 GPH runnign along at 3600-3700 and about 12.5GPH at 4000RPM's. It actually burned more at 3400 than it did at 3600 though, and this is where a fuel flow meter is worth it's weight in gold.