why is my 300 Sundancer going thru some much fuel?????

SeasTheDayAz

New Member
Jun 28, 2010
1
arizona
Boat Info
300 sundancer da 2005
raymarine c seriers nav.
Engines
twin 5.0 mercruiser w bravo III drives
2005 300 Sundancer with twin 5.0's

We are new at owning a searay and do not understand why the fuel consumption is big. We have several friends that own the same boat and some with bigger engines and do not go thru the fuel we do........and drive more then we do.
We need some help and advise....
What could be going on???????
 
First you are burning a lot of fuel because it's a heavy boat with big engines. What are you calling burning too much fuel? Look at your smart craft gauges and see what the burn rate is. If you've compared those numbers with others - maybe something as simple as trim tabs are down, engine not trimmed right or you are just going too fast. I have an '05 280 Dancer with the twin 4.3's . . .and I'm surprised at my burn rate - 10GPH per engine at 3500RPM's. I usually cruise between 3200 and 3500 - just enough to keep it on plane.
 
I agree with the comments above.

Do you know what your burn rate is at any given speed (GPH)? What boat did you own before the 300DA? I know that moving from my 240SD to my 260DA more than doubled my fuel usage and at first it was a bit of a shocker.

Dave
 
I agree with the comments above.

Do you know what your burn rate is at any given speed (GPH)? What boat did you own before the 300DA? I know that moving from my 240SD to my 260DA more than doubled my fuel usage and at first it was a bit of a shocker.

Dave

What do you guys burn trolling,6mph. GPH
 
2005 300 Sundancer with twin 5.0's

We are new at owning a searay and do not understand why the fuel consumption is big. We have several friends that own the same boat and some with bigger engines and do not go thru the fuel we do........and drive more then we do.
We need some help and advise....
What could be going on???????

We need some facts and figures to determine if you have an issue.

We want to help you but with no data we can only offer guesses.

Do you have a GPS with a trip odometer?

Please fill, reset your trip odometer, keep GPS on at all times when you are using the boat, fill again and keep track of your miles traveled and fuel consumed.

Do this a few times in a row then report back.
 
You say friends with similar boats and engines are using much less. Are you sure no one is out joy riding in yours when you are away? ( yes it happens.. one of our own here on CSR had someone watching their patterns and figured out they only came down on weekends. The member thought someone was just stealing gas until a slip neighbor happened to see their boat going by in the middle of the week and asked them about it )

Is their bottom growth? when was it last tuned up?
 
I have a dock neighbor and friend that says he get great fuel mileage - but in reality they don't - A friend and old dock neighbor says he gets almost 3 miles to the gallon on a 330 Larson. Take what others say with a little skepticism.

My dad has a 290 Amberjack with 5.0's and Bravo III's and while cruising he get's about 1.5 miles to the gallon. You should be in the same ballpark.
 
I've got the 310DA with twin 5.0 MPI/Bravo IIIs. Expect 1.2-1.5MPG (tailwind vs headwind).
Some things that I've noticed that lower the MPGs:
1. Growth on the bottom.
2. Thermostat staying open (runs cooler, therefore richer)
3. Using trim tabs while on plane (I'm still a newbie - it's all a learning experience)
4. Props bent/gouged/wrong (not personally, but you never know when buying used)
 
My 2001 270DA (wide beam 270) with a single 7.4 and Bravo III running at 3500 RPM (30 MPH on the GPS) fully loaded with 100 gallons of fuel, 28 gallons of water, weekend provisions, and 4 passengers (approx 10000 lbs - my guess) consistantly gets 1.8 MPG on a 90 mile ICWW trip. With a larger (heavier) boat and twin 5.0's, you should expect considerably less MPG (IMO).
 
We'll be on the lake today and I'll make a chart at various RPMS, GPH and MPH. We just finished annual maintenance and bottom/outdrive painting. This will be a nice record for us in the future and give you a snapshot of the same boat/engine combo fuel consumption.
 
OKay, I have an Excel sheet but don't know how to post it. Can someone give me a hint??? :huh:
 
So far no one has offered a way to post an Excel spreadsheet, but the guys saying they acheive 1.8 MPG may be stretching things a tad bit. My best cruising efficency is
app. 1.32 MPG. This is acheived with engine hours at 126 and 128 port and starboard and a relatively even load on the boat, and no wind. THe props have been polished and the bottom paint is new.
 
I don't know how to directly link the PDF, but if you search Google for:
searay.com tst_9.pdf
and look at the V-drive vs Stern Drive PDF, I think you will see that you're doing just fine MPG wise.
 
Hey Sparky,
Believe the 1.8 MPG figure; I get around 2 MPG lightly loaded in my 290- those of us with single engine and B3 do burn much less than you with (any) twins.
 

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