How long does a tank of gas last ya?

[baconbiscut]

A full tank or 60 gallons lasts me about a 9-10 hrs on our formula. Its 25 feet long and weighs about 7000lbs with A mpi 6.2 liter mercruiser. The boat is a 1986. What kind of fuel economy do you guys on the forum get. Anybody with a similar boat it would be interesting to know.

 

[dingbat]

Re: How long does a tank of gas last ya?

I've got a 22' that weighs roughly #6K at battle weight. The main tank is 92 gallons and my aux holds 52.

I'm running a 225 HP outboard so figure roughly 23 GPH running WOT (40 mph) Most days I can make it home on the main tank but have switched over to the aux to get home a few times.

 

[jack7771]

Re: How long does a tank of gas last ya?

Okay, let's hear it from everybody.

1986 16' Starcraft with 110 hp Evinrude. Weight of boat and motor is approx 1500 lbs. with nobody in it.

I have figured that, with 4 people, at WOT (38 mph) I get apporx 3-3.5 mpg. That's around 11.8 GPH. At 27 mph I get approx 5-5.5 mpg -- that's around 5.2 GPH.

 

[baconbiscut]

Re: How long does a tank of gas last ya?

My aluminum boat with the little 5.5hp johnson on it chugs about 1-1.5 gallons an hour at wot rpm. It moves along at a good clip of about 12mph thats about 40-miles of travel on a tank of gas pretty cool little river boat boat if your on a tight gas budget.

 

[tashasdaddy]

Re: How long does a tank of gas last ya?

baconbiskit, you forgot to mention the the powerplant and outdrive are new.

i get about the same fuel usage as you with the Chris Craft Deck Boat 5.7L

 

[Ezrider_92356]

Re: How long does a tank of gas last ya?

i havent ever calculated my mine but iv gone out fishing for over 12 hours on various diferent trips and used between 2-4 gallons thats varried from anchored to trolling at idle speeds trolling with electric and running wot between spot to spot at around 30-35mph with an 25hp mariner on an 14ft'er

 

[tashasdaddy]

Re: How long does a tank of gas last ya?

when you figure the average engine in a vehicle, of that weight, and engine that size, it runs at highway speed or around 3000 rpms. your probably running an average of 4000rpms. so the comparison is not bad in my opinion.

 

[Bamboo]

Re: How long does a tank of gas last ya?

On my key west 186 w/ Yam F150 I get about 15-20 hours per tank full (60 gal) doing general running around. Fuel flow is about 5 gph at 25-28 mph. At WOT, about 47-48 mph, it runs about 14 gph. Where I boat there are a lot of manatee zones so I get a lot of 1-2 gph time on an average tank.

 

[baconbiscut]

Re: How long does a tank of gas last ya?

On my key west 186 w/ Yam F150 I get about 15-20 hours per tank full (60 gal) doing general running around. Fuel flow is about 5 gph at 25-28 mph. At WOT, about 47-48 mph, it runs about 14 gph. Where I boat there are a lot of manatee zones so I get a lot of 1-2 gph time on an average tank.

We have alot of manatee zones here to. But Our 25 footer likes its drink. When formula designed our boat back in 1986 they only put a 60 gallon tank in it. About amonth ago we repowered it with a New MPI 383 mercruiser engine with a new bravo one drive. The old engine from what I was told din't do so well on gas. It was a 350 and was carburated. At cruise which is 3200-3500 we run about 20-22 mph and use about 4-4.5 gallons an hr.

 

[Bamboo]

Re: How long does a tank of gas last ya?

I know you asked about similar boat with mercruisers and v-8s but thought I'd toss out some outboard numbers just for fun. I've had a few mercruisers in the past (4.3l and 5.7l, and one 455 Olds Rocket) and understand about their thirst at high throttle settings, but at reasonable cruise speeds they don't do too bad. The last v-8 I had was a 5.7L mercruiser on a 23' searay. I think it had a like a 55 or 58 gallon tank. It didn't have any fuel management instrumentation, but it seemed like we'd have to fill it up every other time we took it out which works out to about about 8-10 hours of general running around for each tank full. Of course, that was a smaller boat and motor than yours.

I'd think that getting around 4 gph on that rig at a 3500 RPM cruise is good pretty darned good.

Around here (Cape Canaveral) there is a lot of salt water and I wanted to try a 4-stroke outboard for a while. So far, it is working out well. I kind of miss firing up a nice v-6 or v-8...gotta love that tone!.

 

[Wotam]

Re: How long does a tank of gas last ya?

>"How long does a tank of gas last ya? "

20 gallons lasts all Winter... or maybe 10 hours in the Summer. :>)

 

[rentalguy1]

Re: How long does a tank of gas last ya?

18' Astro with a 115 Mercury Optimax outboard (app. 2000lbs.): 1 gallon/hr with 2 adults and a 10 yr old on board at 4000 rpm (5500 rpm is WOT). I can't complain.

 

[sickwilly]

Re: How long does a tank of gas last ya?

19 ft open bow with 4.3 merc carb -- a full 35 gallon tank of gas will last for two solid days of boating, pulling tubes and skiing.

Maybe longer, but my gas gauge sucks once I get to 3/8th or so of a tank, and it eventually freaks me out enough to go put in gas.

 

[jack7771]

Re: How long does a tank of gas last ya?

Hmm,
>18' Astro with a 115 Mercury Optimax outboard (app. 2000lbs.): 1 gallon/hr...at 4000 rpm<

I've got to say that is really suspect -- have you done a measured run to verify that?

As sickwilly said,
>will last for two solid days of boating, pulling tubes and skiing<
But, that is not a measured test. I too can go many more hours pulling tubes and skiing, but that is deceptive -- there is a lot of stopping, picking up skis,, skiers, changing to tube, changing skier, taking a break, etc.

However, if you fill up, then actually run a measured course at a certain mph/rpm for a timed period (like at least 1 hr) and then refill, you get true measurements. Or, you don't need a measaured course -- just a measured amount of time at specific mph/rpm.

 

[rentalguy1]

Re: How long does a tank of gas last ya?

I fill every time I go to the lake (at least until I am comfortable with the boat). So I've started with a full tank a few times and purposely ran it for 2 solid hours at 3500 rpm once, and once at 4000 rpm for two hours. Each time I pulled back on the trailer and went straight back to the gas station (to the same exact pump...lol) and topped her off. At 3500 rpm it was 0.75 gal/hr, and at 4000 rpm it was 1 gal/hr. However, if I put more people on board, and/or run closer to WOT, then the usage goes up exponentially. Of course the opposite applies if I'm sitting in a cove for a while, or slow-trolling and watching the fish finder.

 

[External Combustion]

Re: How long does a tank of gas last ya?

7,500 lb 30 footer, eight people and gear 240 miles in 30 hours on 1500 lbs of wood!

15 ft MFG with a 85 hp Evenrude around 3 hours tubing and pulling skiers, 12 hours putting at cruiseng speeds (below step for sure!)

14 ft aluminum rowboat either a 7.5 hp Scott-Atwater, or a 5 hp Seaking , both give around two hours at 1/2 to 3/4 throttle. Then there is the abortionite rig that a buddy and I made one day using a vertical shaft Briggs off of a used lawnmower hooked to the lower end of an old Martin. I get around an hour on the tank, as well as the laughs and comments of others. Gotta have fun in life!

As you can see speed is not a concern of mine though. What does the EPA say? "individual results may vary".....

 

[QC]

Re: How long does a tank of gas last ya?

FWIW my 6.2 MPI 320, 23 foot bowrider averages a little better than 3 MPG. I have 2 x 27 Gallon tanks. The longest run I have made is 130 miles.

Our 25 footer likes its drink . . . At cruise which is 3200-3500 we run about 20-22 mph and use about 4-4.5 gallons an hr.

I challenge this only because fuel calculations are really important for all of us to have good solid references to. I think those numbers have to be incorrect. That pencils out to 4.9 - 5.0 MPG. I know of no gasoline powered 25 footer that can achieve that MPG at that speed, maybe at idle. Most barely make 3 MPG anywhere on plane. My guess is that you are using at least 7 GPH . . .

 

[rogerwa]

Re: How long does a tank of gas last ya?

25' pontoon with 90Hp Nissan.. Roughly 9 gal/hr. WOT. I have a 6 gal tank so I ususally carry a second fuel can and refill on the water.

It does not seem to matter if I have three people or ten people on board. It seems to burn the same, I just don't get there as fast.

 

[dingbat]

Re: How long does a tank of gas last ya?

I fill every time I go to the lake (at least until I am comfortable with the boat). So I've started with a full tank a few times and purposely ran it for 2 solid hours at 3500 rpm once, and once at 4000 rpm for two hours. Each time I pulled back on the trailer and went straight back to the gas station (to the same exact pump...lol) and topped her off. At 3500 rpm it was 0.75 gal/hr, and at 4000 rpm it was 1 gal/hr. However, if I put more people on board, and/or run closer to WOT, then the usage goes up exponentially. Of course the opposite applies if I'm sitting in a cove for a while, or slow-trolling and watching the fish finder.

So you ran around at 4000 RPM for 2 hours and only put 2 gallons of gas back in the tank? Got to be pushing 20-25 MPG

I use more than that trolling with my 15 hp kicker at slighly above idle.

 

[Esox]

Re: How long does a tank of gas last ya?

I've never calculated my fuel usage but, on average, I can go out about 6 full days on a full tank before I feel the need to put gas in it. 150 OB/18' Aluminum deep v/45 gallon tank. Of course I have to charge the trolling motor batteries after every trip out.