How do you read high fuel consumption on 3.0 litre

[Gods Favor VIP 1800]

How do you know if your not getting good gas millage on your 3 litre merc.
I was told 30 mph @ 3000 rpm = 3 gallons per hour in my 18 foot VIP.
My math says thats 10 miles per gallon. Would this figure seem real good?
I have seen ads for newer boats saying 3 to 6 is considered normal.
But they were fuel injected 6's or v8's. So is 10 mpg really not that bad
for a 20 year old boat and motor??? With my new Dolfin on the back I may pick up even more mpg ....

The Sea Hag

Gods Favor

 

[Chris1956]

Re: How do you read high fuel consumption on 3.0 litre

I would consider 10MPG to be good for any planing boat of that size. Did you confirm the 3GPH @ 30MPH? figure? I always thought my 19 SeaRay 4.3LX got about 4-5 MPG, but never really tested it.

 

[Haut Medoc]

Re: How do you read high fuel consumption on 3.0 litre

Ten MPG is phenominal, IMHO......
Try 3 mpg for my 22' Sea Ray with a 302......​

 

[JimS123]

Re: How do you read high fuel consumption on 3.0 litre

I have a similar rig and get 6+ mpg. Every test report I have read over the years show 5-6 mpg for the 3 liter.

My personal data for the hydrofoil show an increase of 0.4 mpg.

I don't believe the 3 gph figure is correct. If that's what the manufacturer says, have them show you a complete test report.

 

[steelespike]

Re: How do you read high fuel consumption on 3.0 litre

My guess your actual mpg would be closer to half of that.Usually
GPH (gallons per hour) is a better way of figuring mileage.
Your boat would be likely to use at least 10 GPH at wot probably more. Cruising at optimum planing speed would likely give about
5 to 7 gph.I don't reccomend a doelfin.It may get you on plane at a lower speed and save some fuel there but overall can increase gph.
Some say they add too much stress to the outdrive.
A much better idea is something like smart tabs.They should improve many aspects of your boats performance from no wake speeds on up.

 

[Gods Favor VIP 1800]

Re: How do you read high fuel consumption on 3.0 litre

The last time we had the boat out we rode around the lake (fairly smooth water)
3 adults on board, full tank. stopped only once for a few minutes. rarely idled.
Run pretty much consistent at and up to about 3000 rpm to 3600 rpm. Total
time about 2 1/2 hours. On the way home I filled the tank up and it took just over 8 gallons to fill . So it must be fairly close to 10 mpg or those figures would be way wrong. I'm very happy with 10mpg . I just wasn't sure whether that figure was good or bad. I guess I'm lucky! The VIP planes quick and rides nice and smooth.

The Sea Hag

Gods Favor:redface::redface:

 

[tommays]

Re: How do you read high fuel consumption on 3.0 litre

Your missing something

On a 3.0 powered boat 5.5 MPG is about as good as it gets


I have a 19' 3.0 with GPS and a networked fuel flow that reads out MPG and GPH on the display at all times for about 1000 miles now

To get to 5.5 MPG it has to be dead calm,slack tide and trimmed just SO a bit of wind or current and your right down to 4 MPG


Tommays

 

[45Auto]

Re: How do you read high fuel consumption on 3.0 litre

10 MPG at 30 MPH would make you a millionaire! Some company would buy that thing to figure out why it was getting such unbelievable gas mileage. Maybe whoever told you that meant 10 gallons per hour?

 

[JoChek219]

Re: How do you read high fuel consumption on 3.0 litre

fuel consumption or gph does not exist in the boating world.... just bust out the wallet and don't try to think about economical... too many factors P