Fuel economy: 2 stroke DFI vs 4 stroke

[berudd]

I can not speak for anyone other than myself. I went from a carbed 1993 Johnson averaging 1.8MPG to my G2 with the same HP and I'm averaging 3.5MPG. Picked up speed and picked up a cleaner system.

OIL I was burning $342 XD 30 oil per year Now I'm right at $240 using XD100. So saving $100. Before anyone says anything about 4c not needing oil. Last time a buddy Brought his 4c in he was Bitching about a 600 oil change annual PM... OH not to mention the 3 changes ($150 a pop) he needed before 30 hours...

Yea love me some 2 Cycle DFI.

you cant justify a new engine on fuel savings alone. You cant put enough hours/gallons on it to make it worth it. Byte time you do you will be getting a new boat or motor anyway.

Sounds like someone is fleecing your buddy pretty good.

[woppercatcher]

Sounds like someone is fleecing your buddy pretty good.

No kidding!

[John__S]

For Yamaha fuel efficiency, you can review the Yamaha performance bulletins :

https://www.yamaha-motor.ca/power_so...erformance.php

Mercury used to have the performance bulletins on their website but they appear to be gone.

I have a Yamaha 250 SHO and use a NMEA interface through a Lowrance interface box to display gallons per hour (gph) and mpg. Previously I had Verado 250 which also had a NMEA interface and it displayed gph and mpg on a Humminbird. The gph versus RPM was very much in line with both the Yamaha and Mercury performance bulletins. I also use the gph and mpg readings to trim my motors for optimum gas efficiency. On my Ranger Z521C with the SHO, there are two RPMs that give the optimum fuel efficiency (2900 - 5.4 mpg and 5000 - 3.7 mpg). The SHO is definitely more fuel efficient at the higher RPMs while the Verado is more efficient when idling around.

I have been looking the fuel burn curves for the new 8 cylinder Mercury 4 strokes. I have not found any 8 cylinder fuel burn curves.

You can find Evinrude fuel burn curves/tables.

[wmitch2]

200 hours per year on engine averaging 30 mph = 6000 miles
6000 miles /5mpg = 1200 gal @ $3/gal = $3600 per year
Assuming 25% better fuel economy with 4S 360 * .75 = $2700 per year with 4S
fuel savings of $3600-$2700 = $900 year
$15,000 to upgrade to new 4S / $900 per year in fuel savings = 16.6 years in payback time
Heck yeah, I'd get one for fuel savings alone!

Don't forget to factor in the savings of NO oil added, but you still have to change the oil at what ever the Mfg suggests too !!

[TOUCH OF CLASS]

I would keep it till it blows there’s no way to save money by upgrading unless it’s a old carb motor and going to dfi or Honda 4 or Suzuki .

[Trickyrick]

Which is why I do not have a good merc dealer. If the one in our area was reputable I would have considered a merc...