Gas milage question

[huntingdad]

I have always had outboards, but recently aquired a 23' cuttycabin with a 5.7 inboard. It holds 68 gallons of fuel. What kind of range would I have without carrying extra fuel?

 

[Gem Morris]

You should expect around 2.5 to 3 gpm. So somewhere around 200 miles. But you should do your own testing to confirm that

 

[Phillbo]

A lot depends on how you run it. My 6.2L is most efficient at about 2800 rpm. I typically cruise around 3200rpm.

 

[Squirrel]

You should expect around 2.5 to 3 gpm. So somewhere around 200 miles. But you should do your own testing to confirm that

And bring 20+ extra gallons just to be safe. Sq

 

[huntingdad]

Thanks for the input. I plan on hauling extra fuel, just in case. Also plan on being fairly conservative on the first long trip. My first trips didn't go beyond Padre, and I didn't get an accurate fuel usage check. Will have to see how the potential shutdown affects my next trip departure date.

 

[Leardriver]

Here are fuel flow charts from Mercruiser for the 350 and 496. Of course weight of boat, altitude, etc all factor in, but you see the RPM range where you are at peak efficiency.

 

[Squirrel]

The sweet spot on my 2050 Bayliner is 3200 rpm/27mph. 25+ years ago we filled at Bullfrog, ran to HITE and filled up again. Got 5.2 mpg. I still run the same Bayliner to this day. Sq

 

[Marina Bum]

WOT, near 5000 RPM you'll likely burn around 20 GPH on a 5.7 inboard. If you cruise at 4,000 RPM you'll use less that 13 GPH. Cutting back on revs makes a huge difference in fuel consumption. Every hull and prop set up is different but hopefully you could run 25 mph at 4000 rpm on-plain netting you around 2 MPG and an absolute range of almost 140 miles

 

[Phillbo]

I have 4blade props so I could run 2800 and stay on plane but don't like to lug the motor. 3200 rpms is my sweet spot. Everything feels right. Motor sounds happy and hull is up out of the water as it should be.

 

[Lake Bum]

My boat is also a 23' cuddy cabin. I have a 75 gallon tank, and can go from Wahweap to Escalante and spend multiple days, then come back. I have done this multiple times. I have a 350 MAG, with a Bravo3 drive, and I cruise about 28 mph in the 3100-3200 rpm range. I bring gas, just in case, but have never needed it.

 

[Trix]

From long ago, prior to GPS accuracy, using map distances. My 210 Sea Ray CC with carburetor 350 got about 4 mpg. My 230 Sea Ray with carburetor 454 got about 3 mpg. Generally cruised 3000 to 3200 rpm. FWIW.

 

[CJR]

I mentioned this before, we had a group a few years ago leave APM and head to Escalante for a day trip. All were Sea Ray 240 SD, Bravo 3"s , 6.2 mag, 350 mag, 350 efi and 305 efi. We had a great time, went way up in Escalante exploring. We all filled up when we got back, I used 47gallons and the others were within 4 gallons of me.