Fuel consumption 5.7 MPI

[Capt_Ed]

Anyone have personal experience with a new 5.7 MPI as far as fuel consumption. I know there is lots of stuff on the web but really looking for someone who may have one. I know there is a lot of variables but let me know what you running it in and I will go from there.

 

[Matty4x4]

I can't give you any numbers but my brother in law had one in in a 20 foot searay and it was pretty good considering the weight on the boat,wide beam and the fact that it was set up for tow sports and got worked pretty hard. The guy he bought it from had it swapped from carb to the MPI when he put a new motor in and told us the difference in fuel consumption was big.

 

[Thunder21]

Well I don't have that exact motor but I'll give you my info incase it helps at all . I just picked up a 26 Hourston with a 6.2 mpi (383 small block) and bravo 3 . It burns 11 gph at 25 mph and 13.75 gph at 30 mph .

 

[Fixit]

ive got a 2008 350 mag seacore (300hp) best cruise i get 2.6mpg at 3000rpm 30mph/ top speed of 52mph at 4900ish

in a 20ft wellcraft v20

http://www.boat-fuel-economy.com/mercury-mercruiser-350-magnum-5.7-fuel-consumption-us-gallons its mpg calc doesnt match my findings***

 

[TenMile]

No longer own a 5.7, however my last 2 boats both had them. Boat weighed ~9000lbs and maxed out at 1.7-1.8 MPG. Once the boat was up on step, MPG didn't fluxuate much unless I absolutely buried the throttle.

Engine used about 14 GPH at 3800, 16 GPH at 4000 and maxed out at 20GPH.

FWIW: Merc makes a device called the Mercmonitor that can interface to any MPI built after 2002. It will tell you the exact GPH (or MPG if hooked to a GPS via your plotter). It can send all the engine data to a NMEA2K network to display on your plotter. It has an "ECO" function that shows you the best throttle and trim position to maximize your fuel economy. Plus, it can send all your engine faults to your plotter -- pretty handy device and pays for itself fairly quickly. I had it installed on both boats with the MPI. Extremely simple to hook up -- simply connects to the ECM pigtail that will be hanging on the port side at the rear of the engine.

 

[bullyjack]

I have a 1985 24' searay with a carbed 383 stroker and bravo3 dualprop 21 pitch. Cruises at 32mph burns 6 gallons per hr, tops out at 46mph and burns 9-10 gallons per hr.

 

[TenMile]

Bullyjack -- I don't think your numbers are correct. A 383 stroker will burn well over 20GPH wide open. Doesn't matter what boat it's strapped to or if it's sitting on the shop floor that engine needs > 20GPH to hit it's max RPMs.

This link posted above is relatively accurate: http://www.boat-fuel-economy.com/mercury-mercruiser-350-magnum-5.7-fuel-consumption-us-gallons

and it agrees with this chart

 

[bullyjack]

Bullyjack -- I don't think your numbers are correct. A 383 stroker will burn well over 20GPH wide open. Doesn't matter what boat it's strapped to or if it's sitting on the shop floor that engine needs > 20GPH to hit it's max RPMs.

This link posted above is relatively accurate: http://www.boat-fuel-economy.com/mercury-mercruiser-350-magnum-5.7-fuel-consumption-us-gallons

and it agrees with this chart

Never ran it to long wide open, took an adverage between cruising and hammering it. Never paid much attention to charts and what says it should or will burn, i just go by the hr meter, speed , and how much fuel i put back in.

 

[Thunder21]

I've got a 383 mpi /bravo 3 with a fuel flow meter connected to a vessel view screen. The engine is fuel injected with 150 hours. I burn 13gph at 30 mph . Your numbers seem low bullyjack .

 

[bullyjack]

My mistake, 269 liters for 8 hrs running comes to around 8.5 gallons per hr.