Poor fuel economy

[K_E_N]

I have a 2004 LSV with around 600hours. EFI 350, not sure what HP that is rated nor what Moomba called that engine combo that year. Regardless, it seems that my fuel economy has declined over the past year. I haven't made any changes with regards to prop or ballast over the past year, just performed routine maintenance. This boat has never been very economical to run, but it has really began drinking a lot of gas lately.
Performance is unchanged. Running and starting have been good. Fuel mixture seems appropriate, haven't noticed any black smoke nor residue near swim platform. The boat does die on occasion if you decellerate rapidly (example, go from 1/4 throttle to neutral quickly, boat will likely die, you have to come off the throttle slowly), but it's done this since I bought the boat. I considered trying a throttle position sensor to fix that problem, but have just learned to live with it.
I'm looking for any suggestions regarding the excessive fuel consumption.

[viking]

I'm assuming you've changed the fuel filters as part of the routine maintenance? How about spark plugs and a general tune up?

[kaneboats]

Uhh, could be the fuel itself. Have you tried looking around for ethanol free fuel. It might make a big difference.

[josemiguel]

to safe gas you should think in changing spark plugs, fuel filter, clean injectors and also wax your boat hull will help the boat to glide better. Good luck!

[K_E_N]

My routine maintenance does include regular changing of spark plugs, fuel filter, etc. I may try some different gas. Where I live, it's nearly impossible to find 100% gas without ethanol, but I may at least try a different gas, been buying from a Shell station.

[jmb]

I run the mid-grade gas in mine. Not sure what grade you are running

[harmsway]

10% ethanol in gas will cut your fuel economy as much as 20%. We always loose about 10% fuel economy in the winter months around here because of the ethanol mix required for winter months.

A new gas station recently opened up "Murphy's" and everyone was coming in and complaining about fuel economy in there vehicles. Loosing as much as 25% of there fuel economy and I finally relized they had one thing in common, purchasing gas at Murphy's. Right on the pump at Murphy's it says as much as 10% ethanol added. Yeah they are a few cents cheaper then everyone else, but it cost you in the long run.

When you think about using 6 gallons of gas an hour 10-20% percent adds up quick.

[rdlangston13]

every gas station here has the 10% ethanol disclaimer on it. i was unaware that you could still buy 100% gasoline.

[jimmobius]

It seems like most of the major cities across the nation require " oxygenated" fuels and you can't seem to get away from it. If you go to other parts of the country with low population , I haven't seen the 10% ethanol labeled pumps. As far as running it in the boats I have noticed no performance difference. The only difference in performance I have noticed is when I go to lower elevation than is here (5280') . E-85 is another story. If your engine is set up for it I would run it in the boat in a heartbeat. Cost is one issue , you do burn more of it but you can tune the engine for more performance. I build/tune/race turbocharged sportcompact cars as a hobby and just last season switched to e 85. They do like the fuel , I can run alot more timing and boost plus 100 octane pump gas was $6 a gallon last year. 116 octane fuel at the track is considerably more. I have run up to 30% ethanol in my old escort and no problems yet. Didn't check the mileage but the power is up a little.
Jim

[jmvotto]

Try this list, we have a few in ny, but this list is great for all moomba owners.

http://pure-gas.org/index.jsp?stateprov=LA