Fuel comsumption

Thunderbear2002 · Oct 30, 2012

I have a 2002 Wellcraft Excaliber Platinum with a Mercruiser 5.0 MPI engine. Anyone have any idea what the average fuel consumption might be? I know RPMs, weight, winds, etc. will affect this but I can't get a good read on this due to a funky gas guage. Any help is appreciated!

26aftcab454 · Oct 30, 2012

Re: Fuel comsumption

Welcome to iboats....
my buds 43 foot Wellcraft Excaliber had 3 -502s . what is the lenght of your boat- post the weight & a photo.

UncleWillie · Oct 30, 2012

Re: Fuel consumption

Re: Fuel consumption

The 5.0L MPI will typically burn about 7gph at a 2500rpm economy cruise, and 16gph at WOT.

JoLin · Oct 31, 2012

Re: Fuel consumption

Re: Fuel consumption

UncleWillie said:
The 5.0L MPI will typically burn about 7gph at a 2500rpm economy cruise, and 16gph at WOT.

I think you meant 3500 rpm. 2500 rpm probably won't keep him on plane. If the boat is in the 19-21' range, those figures are probably close. We need more info about the boat.

My .02

Mischief Managed · Oct 31, 2012

Re: Fuel consumption

Re: Fuel consumption

5.0 MPI will burn much more than 16 GPH at WOT. Closer to 23 GPH. At a typical cruise, assuming it's propped correctly, it would burn about half the WOT GPH.

drrpm · Nov 1, 2012

Re: Fuel consumption

Re: Fuel consumption

According to the data I've seen the 5.0 MPI will burn around 7.5 GPH @ 3,000 RPM and around 19 GPH @4,800.

QC · Nov 1, 2012

Re: Fuel consumption

Re: Fuel consumption

Almost all 19 - 21 footers with V8s get from 3 - 4 Statute MPG at cruise. 10 GPH makes her go 30 to 40 MPH as an example. Uncle Willie's link proves out that a 2500 RPM cruise is possible depending on boat size. Most boats that run above 50 MPH will plane reasonably well at 2500 RPM (I/O V8 discussion).

The OP needs to use his refill amounts to figure out his gauge. And he needs to figure out distances traveled to make any sense out of it.

jestor68 · Nov 1, 2012

Re: Fuel comsumption

Replace the funky gas gauge.

UncleWillie · Nov 1, 2012

Re: Fuel consumption

Re: Fuel consumption

There is often nothing wrong with the fuel gauges on boats that can be fixed.
They are notoriously optimistic because the tanks are often not rectangular, the senders are in the rear of the tanks, the senders are linear, and boats are seldom sitting level.
They read nearly full until below 1/4 and then indicate empty a very short time later.

If you want to have a Snowball's chance of accurately knowing how much fuel is remaining, get a Fuel Manager Gauge.
It measures the amount of fuel that has been used instead of how much is still in the tank.

Mischief Managed · Nov 2, 2012

Re: Fuel consumption

Re: Fuel consumption

drrpm said:
According to the data I've seen the 5.0 MPI will burn around 7.5 GPH @ 3,000 RPM and around 19 GPH @4,800.

That WOT GPH number works perfectly for a carbureted 220 HP 5.0, but not a fuel-injected, 260 HP, 5.0. You can't make 260 HP with only 19 GPH on a small block Chevy gas engine.

QC · Nov 2, 2012

Re: Fuel consumption

Re: Fuel consumption

Beg to differ MM. Check Uncle Willie's link above. Here is on example. Slightly under 19 GPH at WOT: Baja?20 Outlaw? Reviews,performance,compare,price,warranty, specs,Reports,Specifications Layout, video | BoatTEST.com

Mischief Managed · Nov 2, 2012

Re: Fuel consumption

Re: Fuel consumption

QC said:
Beg to differ MM. Check Uncle Willie's link above. Here is on example. Slightly under 19 GPH at WOT: Baja*20 Outlaw* Reviews,performance,compare,price,warranty, specs,Reports,Specifications Layout, video | BoatTEST.com

I see that. Hmmm, seems odd to me. Here's another 5.0 MPI that uses 23.4 GPH at WOT: Sea Ray?240 Sundeck (2011-)?2011? Reviews,performance,compare,price,warranty, specs,Reports,Specifications Layout, video | BoatTEST.com

QC · Nov 2, 2012

Re: Fuel consumption

Re: Fuel consumption

Yeah, the rest are pretty consistently under 20. Looks to be RPM related for sure. Those that are at WOT the lowest seem to meet the 18 GPH, higher RPM and they begin to break 20 like your example. There were some that were under 17, but they were over-wheeled for sure

This type of fuel rate per hp developed is generally consistent with all of the MPIs. The 5.0 260 is a great powerplant. Based on test data, and some personal experience with a friend's boat, I argue against the 5.7 only mantra that is often used here. I firmly believe these 5.0 MPI's outperform older carbed 260's (prop or flywheel) in every respect including hole shot (torque). Especially good with B3s in twin applications in say a Cruiser where everyone always says I am a fool for suggesting a 5.0 is acceptable.

aerobat · Nov 2, 2012

Re: Fuel consumption

Re: Fuel consumption

my parents have a 2010 sea ray 240DA with the 5.0 MPI which is equipped with the electronic flow meter in the cockpit and i can say for sure it burns 88litres / hour which is roughly 23 gallons at WOT . all this at 4700rpm pushed on the bravo III drive .

but thats one point- in the mix of the day which is trolling, cruisng etc this engine is fuel efficient- the fuel bill is not significantly higher than with my 21 footer cabin and 3.0 Volvo penta engine.

emilsr · Nov 2, 2012

Re: Fuel consumption

Re: Fuel consumption

drrpm said:
According to the data I've seen the 5.0 MPI will burn around 7.5 GPH @ 3,000 RPM and around 19 GPH @4,800.

That's exactly what I saw with my 5.0 mpi powered 20' bowrider. May have been the most fuel efficient boat I've ever owned....which makes me wonder why I got rid of her. :facepalm:

Thunderbear2002 · Nov 2, 2012

Re: Fuel consumption

Re: Fuel consumption

Thanks for all the advice.
The boat is a 21' bowrider, approx. 3000 pounds.

aerobat · Nov 3, 2012

Re: Fuel consumption

Re: Fuel consumption

when it comes to fuel burn per hour at WOT the engine does not care how big or small the boat is.

QC · Nov 3, 2012

Re: Fuel consumption

Re: Fuel consumption

Agreed aerobat, but if "mileage" or distance is part of the concern then weight and size translate into boat speed which determines the range possible on a tank of fuel. This is why I always argue that GPH is meaningless without speed. Can't do much planning with it unless you simply like to go around in little circles.

aerobat · Nov 3, 2012

Re: Fuel consumption

Re: Fuel consumption

thats obvious and of course fully correct QC. how much an engine burns per hour is one question- the big second question is of course how far will you travel in this hour.

Mischief Managed · Nov 3, 2012

Re: Fuel consumption

Re: Fuel consumption

QC said:
This type of fuel rate per hp developed is generally consistent with all of the MPIs. The 5.0 260 is a great powerplant. Based on test data, and some personal experience with a friend's boat, I argue against the 5.7 only mantra that is often used here. I firmly believe these 5.0 MPI's outperform older carbed 260's (prop or flywheel) in every respect including hole shot (torque). Especially good with B3s in twin applications in say a Cruiser where everyone always says I am a fool for suggesting a 5.0 is acceptable.

Not my MPI... My 310 HP 7.4 MPI burns just over 26 gallons per hour at WOT. That's almost perfectly in-line with 260 HP and 22 gallons per hour. I'm thinking that the 5.0 MPIs burning only 19 GPH are truly not making the full 260 HP, perhaps due to being over-propped to keep the RPM down.

Fuel comsumption

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