Thread:

300 promax to 300xs fuel use?

I am really contemplating doing a repower on my boat with gas heading once again the way it is. I was looking for some input on some real life numbers on what i could expect from people who have the 300xs motors versus the standard 300promax motors. thanks!

thanks alot for that comparison man that is something i really wanted to hear. I am doing the math right now and i would save so much money at fuel being $4 a gallon let alone if it goes to $5!

Originally Posted by Rayzor

300XS motors will burn half of what your 300PMs use. I had a 28 Skater w/ 300PMs when a friend of mine had his 30 Skater w/ 300XSs and when we would go out together for the day he would burn right about half the gallons I did. Same speed, same distance, very similar boats. I'd say that the XS performance is just about identical to the PMs. The XS motors are definetly not as strong as the X motors though. I'm putting an XS on my 21 Trick, they're the only way to go with todays economy and fuel prices!

dustin real world running , heres are equation 5 days boating on havasu couple trips too the sand bar two trips too needles and a trip for breakfast at the springs sat morn the day of poker run i only spashed 50 $ more on top off the inital 300 $ for the weekend which was a just in case scenario ended up coming home with a little of that 50 bucks still in the tank ! hows that TUNNEL T




p.s. do it you won't lose anything and you'll be putting money back in your pocket!

wow anthony that is crazy, i run from needles all the way to havasu all the time and use way to much fuel. I am going to call drew right now and talk to him about it, not sure if i want to wait till after the summer though and get one more season out of these motors since i won't be using the boat just quite as much as last summer.

Originally Posted by TUNNEL T

dustin real world running , heres are equation 5 days boating on havasu couple trips too the sand bar two trips too needles and a trip for breakfast at the springs sat morn the day of poker run i only spashed 50 $ more on top off the inital 300 $ for the weekend which was a just in case scenario ended up coming home with a little of that 50 bucks still in the tank ! hows that TUNNEL T




p.s. do it you won't lose anything and you'll be putting money back in your pocket!

Straight from Mercury Racing's mouth to me via phone 300xs burns 30gph at WOT.

So if you have a single engine cat that does 90 mph and you held that puppy wide open for an hour you'd get 3mpg

I'm assuming your burn is better at lower rpms but Merc doesn't do testing on that.

He did say a 250xs is 25 gph at WOT.

Originally Posted by BigSteve

Twin 300xs on your hull, from 65-95mph will be close to 3 mpg on the smartcraft readout

The fuel milage drops off over 6000 rpm to about 2.6 mpg

Hello BigSteve:

This thread is funny. I am doing mileage calculations as we speak Miami to Bimini and then to Bahamas followed by Key West.

Twin 300XS on a 32 footer with 130 gallons of fuel. Estimation of mileage is 260 total miles. Each motor will burn 2.5 gallons of fuel per mile estimate each tank is 65 gallons of fuel. Thus, each motor will burn all 65 gallons of fuel in 162.5 miles at a cruising RPM of 5750RPM if you use tthe 2.5 figure.

Now if you use the 3 miles per gallon extended cruising range is 195 miles.

NOTE:Vessel does not have smartcraft system so calculations need to error on safe side.

The hourly burn rate doesnt help me one bit. I need to know the distance traveled on two gallons of fuel. I was wondering about the twin motor co-efficiency and how to calculate this variable.

I really do not think anyone can tell the exact mileage and burn rate. Also in the ocean you are never just at one RPM your in it... then out... then back in it.

Drejustice you have smartcraft what is your fuel capacity and how far can you go?

Then figure the average mileage to your burn rate with your twin engine boat what do you come up with. I do not remember if you have a chartplotter telling you distance travelled.

KAP

Originally Posted by Rayzor

Hey Kap, why such small tanks? My 28s held 70 per side and my 30 holds 100 per side. My 28s w/ 3.0s would plane off without any problems full of fuel with 5 people on board. I would guess you could make the tanks at least 80 per side without any planing issues. And the extra weight won't hurt you out in the ocean!

Comment:

Good question Dale!

This boat we are gonna use has 65 gallon tanks. This amounts to $585 dollars to fill up at $4.50 dollars a gallon. I can have 100 gallon tanks if I wanted but I mean really how often am I going to put that much damn fuel in it.

We went 88 miles in the ocean and I was friggen tired looking for a cantina. Now change the 88 miles to 150++miles and all I can say is...no thanks. One of the guys in Miami doesn't know what his burn rate is or potential mileage on a tank.

I wanna go out with someone who knows were the hell they are going. Plus, the fuel calculations always come up. I want to be as informed as possible. In the ocean if we go out any distance I always want to be loaded with fuel and water.

Interesting how many different opinions you get on consumption for these motors and no one knows how many miles they get on a tank of fuel. I will know this to a tee when I get my boat I can envision days were I will run the hell out of it.

Drejustice you should know you have a Garmin 740 Chartplotter and it should tell you exactly the amount of distanced travelled on a tank of gas.

KAP