Fuel economy on boats

[tmitchell5188]

I know that this is high on everyone's list these days, but I'd like to ask what fuel economy people have observed for 21' and 23' walk arounds. I'm thinking of going to a smaller boat, and I'm looking for what boat/engine combo's fuel usage is.

I'm interested in Mercury Optimax, or 4 stroke. I think that a 21' boat would use a 150HP outboard, and a 23' would probably use a 200HP outboard. I'm also looking for something that can take 3 or 4 guys fishing.

Thanks.

 

[marine4003]

Re: Fuel economy on boats

Thats not an easy question to answer, there are too many variables, like what kind of boat,hull style,weight,water type (salt/fresh) total weight ect..it may make a huge difference.
But generally speaking the Optimax 175 will go thru 6 GPH @ 4000 RPM giving you about 5 MPG...It goes up from there.
http://www.mercurymarine.com/look_d...=Title&Section=outboardChecks&optimax135175=6

 

[dingbat]

Re: Fuel economy on boats

I have a 22' Walkaround with 200HP 2 stroke outboard. The performance is decent but it could certainly could use a few more ponies on the transom. Now that my manufacturer has gone all 4 strokes they don?t even offer a 200HP on my boat if that tells you anything.

Before this I had a 21? by the same manufacturer and it had a 175HP 2 stroke on the back. Again performance was decent but more would have been better.

As for fuel mileage, on the 22' at 4000 rpm cruise (@26 kts.) I'm burning between 12-14 gallons an hour. That works out to roughly 2 MPG.

The same boat powered by a 225HP 4 stroke would get roughly 2.8 mpg. Put a 250 HP on the back and that number jumps to 3.3 mpg.

Same holds true for the 21'. A 150 HP 4 strokes gets 3.8 at cruise while the 225 HP gets 4.2 mpg at cruise.

What that tells you is that smaller isn't necessarily better if you?re under powering the hull. Real life performance figures from the boat in question is the only real method of comparison.

 

[tashasdaddy]

Re: Fuel economy on boats

the only way to conserve fuel is to go to wot, then feather back the throttle. motor are made to keep the spark advanced, and the throttle plates back off to save fuel, been like this for many years. or stay at the dock.

 

[wildmaninal]

Re: Fuel economy on boats

the only way to conserve fuel is to go to wot, then feather back the throttle. motor are made to keep the spark advanced, and the throttle plates back off to save fuel, been like this for many years. or stay at the dock.

I have no idea how good my '78 85hp Evinrude is on fuel. I have been known to do the same as TD just mentioned, feather back the throttle. I went out 3 days in a row 2 times on 2 days 1 time on the last day momorial weekend on a 6 gallon tank of gas. This all on (1) 6 gallon tank of gas. I was about on E when I trailered and parked the boat and pulled the tank out. From where we launched and docked at for those 3 days to where we went fishing each day was a pretty good drive in my opinion. The power pack went out on the 2nd night so I would of had more fuel left, but on the 3rd day I had to spin it over and even run it to diagnose the problem.

 

[AguaSki]

Re: Fuel economy on boats

The OMC v4's are known for being thirsty, but I just got 3.3 mpg out of my 1978 140 hp Johnson at Lake Powell. The boat is a 18 foot Glastron, and I was carrying 4 adults and 2 children. The key to my good mileage was the speed we traveled at. I kept a steady 3,900 RPM which pushed the boat at about 26 mph. I was considering a repower to a newer fuel efficient outboard, but I am now very happy with how my old motor performed. I do like to hear my outboard scream at WOT, and it does suck the gas when I do that, but for a big sight seeing lake like Powell, I found running at 3,900 rpm was just right. I think driver behavior will contribute the most to good gas mileage.