Fuel consumption

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bruc
Posts: 9
Joined: Fri Oct 26, 2018 2:48 pm

Fuel consumption

#1 Post by bruc » Fri Dec 14, 2018 9:51 am

We purchased a new Princecraft 19' pontoon boat this fall and hadn't had the opportunity to take it out being so late in the year. It has a new Mercury 50 hp. outboard engine and a 6 gal. has tank.We plan on just puttering around the lake and will not be trying to pull anything or run wot and will not have any more than 4 people at a time and usually just the 2 of us.I am wondering just how long I can plan on going before having to refuel,and if it is worth my while to get a larger tank or a secondary one.Does anyone have any info. on what I can expect for fuel consumption and any other advice on what I should consider? Thank you in advance for your help.

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Liquid Asset
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Joined: Tue Jan 03, 2012 12:21 pm
Location: ortonville,mi

Re: Fuel consumption

#2 Post by Liquid Asset » Fri Dec 14, 2018 2:21 pm

If you're just doing slow cruising that 6 gallons will last a long time. Hard to say exactly but I know when I had a old 2 stroke 50 on my current boat ( motor that came with it before the rebuild) I could spend most of a day with a mix of speeds and only use six gallons. My tank in the transom was 9 gallons. I always had range anxiety on bigger lakes ( still small compared to what many here boat on) so I would carry a 3 gallon external tank. I never had to use it but felt better knowing it was there.

This same boat (20' rebuilt into a tritoon) now has a 90 on it and a 18 gallon tank in the transom. I can have a load of people and tow my kids and their friends and still have plenty of gas at the end of the day.

If you can get a bigger tank before you use the boat it wouldn't hurt. Not sure if it is a portable type or mounted to the boat. Also the size of the lake matters. If it is just a small lake and you're not far from the dock/launch just keep an eye on the fuel level. You will figure out how much you use.
2018 Tahoe ltz elite windshield powered by a 175 Mercury verado with sea legs
Rebuilt custom 20' 1983 riviera cruiser tritoon SOLD

2017 crew cab F-350 gets me to the lake !

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steve1313
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Re: Fuel consumption

#3 Post by steve1313 » Fri Dec 14, 2018 2:26 pm

Here's a good website to show you estimated fuel burn.

http://www.boat-fuel-economy.com/mercur ... us-gallons
Steve
"Serendipity" - 2017 Sweetwater 2286 WB Tritoon w/ 150HP Yamaha
Slipped at Lake Anna, Virginia
Primary Residence: Richmond, Virgina
Lake House: Lake Anna, Virginia

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Liquid Asset
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Location: ortonville,mi

Re: Fuel consumption

#4 Post by Liquid Asset » Fri Dec 14, 2018 2:56 pm

Thanks for sharing that website. I was just playing with the consumption on my new yet to use motor. I'm both happy and sad to see what it should use lol!!!
2018 Tahoe ltz elite windshield powered by a 175 Mercury verado with sea legs
Rebuilt custom 20' 1983 riviera cruiser tritoon SOLD

2017 crew cab F-350 gets me to the lake !

Oldchuck
Posts: 72
Joined: Sun Oct 14, 2018 10:19 am
Location: Central Florida

Re: Fuel consumption

#5 Post by Oldchuck » Fri Dec 14, 2018 3:51 pm

Steve,
Thanks for the website.
Old school figuring was 1 gph for every 10 horsepower used. This chart is very close. I have a 150 Yamaha 4 stroke which is said to have more than 150 hp and my actual fuel burn WOT is 16.5 GPH which is more than the chart shows but close to what the rumored HP of that motor is.
However, if I stay around 3300 then my actual fuel burn is around 5 GPH so if the 50 HP Mercury will burn 5 GPH WOT then around 3,000 RPM I would assume the actual fuel burn to be around 1 GPH or close.. Bottom Line- that 6 gallon tank will last a long time and if you carried another 2.5-5 gal can then I doubt you could burn all your fuel in a days running...

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Marc K
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Re: Fuel consumption

#6 Post by Marc K » Fri Dec 14, 2018 9:04 pm

My old Yamaha F115 on an old, heavy boat seems to use about 5 gallons per hour at a leisurely 4300 to 4400 rpm at about 15 mph. This is where I tend to cruise if I'm headed up lake. Of course my fuel consumption outpaces my MPH as I throttle up - especially being a two tube model. I have a feeling that Chuck's rule of thumb is darned good!

In my case:
2800-2900 rpm uses around 2.5 gallons per hour at about 10 mph.
5400-5500 rpm consumes around 7.5 5o 8 gallons per hour at about 22 mph.
6000 rpm (wide open) only gains 2-3 mph but jumps to a little over 10 gallons per hour.

My boat came equipped with two 6 gallon plastic tanks that fit in the well behind the rear seat, under the sun deck on the port side. My first thought was that I needed a real gas tank!

Well.......I added another on on the starboard side, and have room for a 4th. But I have never used more than 12 gallons on a single trip. While we may travel a good number of total miles in a day, we are rarely more than about 15 miles (35-40 minutes, 4 gallons) from home. Living on the lake changed my planning, because I can always head home get someone/something. Keep in mind that 12 gallon "high profile" (16"high) tanks are available with the same footprint as the 6 gallon tanks - just taller. (Moeller and others)

And for what it's worth:
This is my first pontoon boat, my first outboard and my first experience with portable tanks. I have to say that the sheer utility of portable 6/12 gallon tanks has really grown on me. I fully understand that my approach and needs are woefully inadequate for some folks, but for MY situation:

Portable tanks are super easy to keep your fuel tank(s) clean and/or dry, especially if you winterize.
Simple to dump any aging fuel into the riding mower/garden tractor/truck, and start fresh.
It is quick and easy to pass a portable tank across to another boater who didn't plan ahead.
Ready access fuel for a little generator on shore if you are camping (eu2000i in my case)
I can add tanks up to 4x12 gallons in the same compartments if I wanted to.

Marc
Last edited by Marc K on Tue Dec 18, 2018 4:33 am, edited 1 time in total.
Big and ugly but we love our 1999/2000 Crest II DL with a Yamaha F115

Oldchuck
Posts: 72
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Location: Central Florida

Re: Fuel consumption

#7 Post by Oldchuck » Sun Dec 16, 2018 6:17 am

Mark,
I think your assessment is right on.
When a young kid all we had were portable tanks and we never had any fuel issues and you could always carry an extra or two for a day's skiing.
Now, with more and more contained and expensive boats they are almost never seen. However, internal fuel tanks can be a pain in the ass with bad fuel, gunk in the tank and the recent EPA environmentally safe from spill fuel tanks with air locks and valves which give many issues in a number of newer boats. With portable tanks you remove many issues before they happen. If you have to replace a newer internal fuel tank it is not an easy task and no dealer can legally take the EPA "protection" out. Mark, you are wise to stick with what you have..
You are also correct in your assessment that you seldom get a good mpg return in the upper rpm ranges and will often burn twice the fuel to get a few mph...

riplipper
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Location: St Augustine, Florida

Re: Fuel consumption

#8 Post by riplipper » Mon Dec 17, 2018 5:13 am

I would think if you lake is more than 10 miles long it would be wise to carry extra fuel. A small 1-2 gallon tank tucked away. Just make sure you empty it every time you refill.That way the gas never gets old.
You could also purchase and install a 10-12 gallon poly tank and mount it where the 6 gallon is?
You also have to consider if you will trailer to other larger bodies of water, always fun to go and explore new areas. We are always doing this with our boat.
I am the guy at the boat ramp that gives you dirty looks when you are a complete idiot and too stupid to know it.

Bamaman
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Location: NW Alabama--Tennessee River

Re: Fuel consumption

#9 Post by Bamaman » Thu Dec 20, 2018 4:35 pm

I always used a 12 gallon portable tank, and I had a 6 gallon OEM Yamaha tank as a backup. I carried much more fuel than required on my boat with a 115 hp Yamaha 2 stroke motor. I've had no experience with shorter, less powerful boats so I cannot address fuel mileage.
'12 Bennington 24' SSLX Yamaha 150

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