Gas Mileage Question/Scenario HELP!!

[Spartan]

I’m running a 1996 Cobra Viper 201D w/ a 1996 Mariner Magnum 3.0L EFI 225. My mileage is really driving me nuts. I’m extremely happy with my boat and its performance, but I’m starting to really feel it at the pumps. Question: Is the 3.OL notorious for drinking gas like a fraternity boy at college?

I purchased the rig April of this year. I was in the shop for inspection and a tune-up. Compression and all other checks passed with flying colors. Also, I had boyseen reeds installed during that time. Other than that, it’s stock. I’m a freak about taking care of it, so it’s never abused. Oh, it also has a 2001 Optimax lower unit. The motor runs excellent, never a problem to start, is a beast on the low end w/ great mid-range power. Top speed WOT (2 people, gear, full tank, tackle, ¼ full livewells) 5600-5800rpm, fully trimmed…..71.4mph. Set-up at 3.25” below the pad, 6” rite-hite manual JP and a 25” four-blade (brand unknown)

Anyone with experience this nagging problem with 3.0L’s?

Last Saturday’s tournament scenario:

Fished the California Delta.
Launched out of Tracy Oasis marina.
Ran up to Stockton (fished several spots between Tracy/Stockton)
Same rout on the way back making several stops.

Total round trip +/- a few miles (85mi)
I have a 44 gallon tank.
Under 2 miles per gallon!

Driving performance that day:
75% WOT
15% cruising/mid range
10% 5mil zones/ misc.

Merry Christmas everyone!!!

[Backlash Ar]

Sorry to say, but your 3.0L engine sucks....gasoline that is. Such is the nature of the beast. The engine is bullet proof but they do use quite a bit of gas and oil...especially at WOT. You will have better fuel economy if you run around 4200-4500rpm's. Your gas usage should be somewhere around 2.5-3.0 mpg. With an EFI, how are you determining how much gas you are using? I ask that because the sending unit was configured, on the earlier Cobra's, in such a way they didn't read very accurately and that was a very common complaint . There always seemed to be anywhere between an 1/8 to a 1/4 tank left when it showed empty on the needle. The only way you're going to be able to tell how much gas is left in comparison to what the needle shows is to siphon it out once the needle shows empty. Then you will be able to get a little more accurrate mpg reading. Looks like your set-up is about where you need it but if you want to try a couple of things....get a bigger jackplate (10") or at least some 2" spacers to make it 8" and raise the engine a 1/4".

[Spartan]

Hey Backlash,

Yup, that gas guage really sucks! Well let me tell you how I know.....about a mile from the marina that day I decide to run out of gas!!!! The darn needle was a hair above empty...and I mean just a hair. When I filled up that morning the gas guage showed empty. I put approx. 34gal in her which then filled her up (it overflowed). So with by basic math skills that would put me at 44gal..right? (10gal. in the tank on empty) I start the morning off on "Fred"(full)...then with my luck....almost to the promise land..poof! I'm putting my foot down and for now on, if I see a gas dock, im going to put some gas in her.

Regarding the set-up you're recommending...what will I achieve vs. cost.

[Backlash Ar]

Should get you up on plane a little faster and that will save a little gas and then you can throttle back to around 4200-4500rpm's sooner and that will save you a little gas too. Also, by raising your engine it will help eliminate some drag because there will be a little less lower unit in the water. Without a hydraulic jackplate there is no way you will ever be able to get the maximum performance because you won't be able to raise and lower the engine depending on the situation so you just have to find the over-all best placement for your manual plate. The 2" spacers aren't very expensive and in the long run would pay for themselves. I had a Hammer 250 V-Max EFI and I needed to tow a gas tank behind the boat...talk about suckin' gas! But that engine was a strong runner, very fast, but I felt I had to get out of it because it was costing me an arm and leg to run it.