Why is this 5.7 drinking SO MUCH FUEL.

[wadyadoing]

Hi havent been on in awhile. Ok here is the deal, 1993 5.7 comp ski serial# of025486 on a 1993 searay spitfire Ive owned the boat since 2002 and in the last few years it has started to drink massive amounts of fuel. Had it out yesterday and started with 391.6 hrs and ended with 394.3 pulling skiers all day at 25 to 35 miles an hour it used 14 gal of fuel. this seems excesive I was only running at 2500 to 3500 rpm. I tuned it up last year plugs cap roter the whole deal and the boat is running great but it is suking up the fuel at an alarming rate. What should I be looking at? any advice will be nice for my wallett. It also requires me to hold the throttle full on to start the boat most of the time I donk know but Im thinking I need to rebuild the carb. But this boat only has 400 hrs.

 

[thumpar]

Re: Why is this 5.7 drinking SO MUCH FUEL.

I think you are on the right track with the carb rebuild. Could be a float issue.

 

[Riegfrghtl]

Re: Why is this 5.7 drinking SO MUCH FUEL.

14 gals does not seem excessive to me. You used 4 to 5 gals per hour pulling skiers. Start and Stop many times is not exactly the most efficient for mileage. Just a thought. Tim

 

[dingdongs]

Re: Why is this 5.7 drinking SO MUCH FUEL.

check your plugs and if there okand you dont have a fuel leak that fuel rate seems ok as your giving the boat some extra work to do by pulling skiers.assume the hull doesn't have barnacles or any growth over it and if it does remove it.

 

[FishHog]

Re: Why is this 5.7 drinking SO MUCH FUEL.

that sounds about right to me for pulling skiers. That kind of driving is hard on fuel, and 5.7L aren't good on fuel in the first place.

 

[Aatcman]

Re: Why is this 5.7 drinking SO MUCH FUEL.

Hi,

I think you gave the biggest clue when you said "and now I have to have the throttle wide open to start it".......

This means it's flooding....

Pull the dipstick -- it may be "making" oil and the oil might even smell like gas............

I think your float is stuck open and fuel just keeps pumping into the carb -- at which point it just keeps pouring down the intake and past the rings........

Another possible cause of flooding you should check is a bad fuel pump.
There is a small rubber line (usually clear or yellowish) that goes from the fuel pump to the carburetor....
Check and see if it has gas in it -- if it does, your fuel pump is shot and is constantly pumping fuel down the throat of your carb -- this is a saftey feature -- in the same condition an automotive fuel pump either leaks directly on the ground or into the crank case...

Hope this helps.....

 

[45Auto]

Re: Why is this 5.7 drinking SO MUCH FUEL.

Had it out yesterday and started with 391.6 hrs and ended with 394.3 pulling skiers all day at 25 to 35 miles an hour it used 14 gal of fuel.

If you have a 1993 5.7L that only uses 5.2 GPH pulling skiers between 25 and 35 MPH I wouldn't touch it. A brand new, lightly loaded, fuel injected 260HP 5.0 uses 7 to 10 GPH at the same speeds just cruising, not pulling anything.