I have a 2006 Ranger 620 with a full windshield, powered by a 2006 Verado 250. I cannot recall which prop it has offhand and I am not near the boat and top end so far has been 59mph around 6200rpm. However, it is obviously quite thirsty at WOT and I have been trying to find a cruise rpm range that would give me the best fuel economy. I have been trying to keep it at 4900-5000 rpm but am clueless if this is even close to optimum.

Could anyone suggest the optimum cruise rpm range for best fuel economy for this rig?

Thanks!

Chech out your smart guages and alter your speed until you see optimum MPG. My old man's Verado (225 on a 2095 Yar) is optimum in that 4000rpm range.

According to the Mercury Website, 3000 rpm is the optimum cruising rpm. (4.2 mpg, it drops to 3.8mpg at 4000 rpm) Depending on conditions, (load, trim, weather). I believe it's the same for my Merc 115. That being said, I usually run around 3500-4000 rpm. Bottom line, as close to 3000 rpm's as you can stand. On your rig, you'd probably have to throttle up to get on plane, then throttle back to that area that offers the best speed/savings. It sucks to have all that horsepower and not be able to use it (afford to use it).
Mike

C'mon. If you can afford the boat you surely can afford the gas. Its well worth the money to open that baby up and enjoy it. It surely cant cost that much more considering your investment.
Full throttle for me and I hope I get to burn the last gallon doing it.

It's been a while since I did the math and read an article on peak operating efficiency of the Verado, but I do recall it was pretty much at 4000 rpm. You should be able to calculate yourself if you've got the smart craft gauges to gather data.

For instance, at 3000 rpm you may be at 7 gallons per hour, and 23 mph speed.

At 4000 rpm lets say your at 11 gph and 39 mph.

With a 50 gallon tank, you would run 7.14 hours and cover 164 miles at 3000 rpm.

You'd run 4.54 hrs at 4000 rpm, and cover 177 miles.

In other words, you'd go 13 miles farther on the same amount of gas running at 4000 rpm.

But then, at 6800 rpm, and 28 gph, and 60 mph, you'd cover only 107 miles, but you'd do it with a smile on your face....

That was one of the good points with the Verado. The optimal cruising speed is several mph higher than the other engine configurations.

It's been a while since I did the math and read an article on peak operating efficiency of the Verado, but I do recall it was pretty much at 4000 rpm. You should be able to calculate yourself if you've got the smart craft gauges to gather data.

For instance, at 3000 rpm you may be at 7 gallons per hour, and 23 mph speed.

At 4000 rpm lets say your at 11 gph and 39 mph.

With a 50 gallon tank, you would run 7.14 hours and cover 164 miles at 3000 rpm.

You'd run 4.54 hrs at 4000 rpm, and cover 177 miles.

In other words, you'd go 13 miles farther on the same amount of gas running at 4000 rpm.

But then, at 6800 rpm, and 28 gph, and 60 mph, you'd cover only 107 miles, but you'd do it with a smile on your face....

That was one of the good points with the Verado. The optimal cruising speed is several mph higher than the other engine configurations.

Exactly

Thanks guys. Next time out I'll give it a try around 4000 rpm and see what difference that makes. I don't mind an extra 5 minutes to the fishing hole. If I'm going to be taking it slower (4 month old baby girl makes three of us and she loves the boat) then I might as well do it at the optimum cruise speed.

Thanks again for all the great advice!

Bobby

As mentioned before...if you have Smart Craft Gages it will calculate that and display it for you as you are running.

I have the same motor on a 2150 Crestliner. My most efficient spot is right around 3500 to 3600 rpm.

Bobby,
I have the same rig except its an 07. Smartcraft says 9.2 GPH running about 30mph.
Thats with a 21" Rev 4 prop. Also have a 4"Bobs Jackplate which makes zero difference
in top end - also about 60 MPH. Vrods are a little thirsty.

DF

Thanks guys.

Dieselrod, when you're at 30mph, do you recall approximately what your rpm's were?

I guess I have some playing to do with my smartcraft guage. I only have the one digital guage in the centre of analag cluster and will fiddle with it to see if I can find out how to calculate my optimum mpg.

Hopefully you've got the SmartCraft monitor manual. If not, here it is: http://www.mercurymarine.com/_media/pdfs/otherproducts/smartcraft_manuals/System_Monitor_Manual.pdf page 7 will lead you to the gallons/hour screen. You can see your fuel flow at various rpms/mph, and see what makes the most sense (to your wallet).
HRG

Bobby,
Not real sure on the RPMS @ 30MPH But I do remember always looking for the 9.2 GPH when heading for the next spot. I also know that @ WOT smartcraft reads 29.3 GPH which tends to suck the fun right out of it !!
DF

I'll definitely download the manual... thanks. Hopefully I can get my head wrapped around figuring that gauge out - couldn't figure it out without the manual so this should be the ticket. I bought the boat as the second owner and have no manuals. Appreciate the link.

Thanks again as well, Dieselrod, I'll watch for that magic number!