Gas mileage on carbed supra

[wakeup]

I may not have posted this in the correct place but here's my question.how much fuel do you guys consume in lets say 4 hours of back to back boarding.
I have a 1988 supra with PCM 351,Borg Warner 1:1 tranny with acme 913 prop,1000 pounds ballet in rear and about 800 in front,Bennett trim tabs. I go thru a about 3/4 of a tank in 4 hours ( give or take a minute)that's with switching riders back to back.
My buddy has 08 launch and he burns less than a 1/4 tank n that time. I know there's alot of difference between fuel injection and him having perfect pass but that much difference. He also sacs out more than me and has usually three more people than I do.
Is it my carb or still having points or what. It's killing the wallet

[wotan2525]

In my experience, the newer fuel injected boats do not get very much better gas mileage than the old carb'd ones. The fuel gauges are incredibly inaccurate... I wouldn't trust that 1/4 drop indicated on the gauge had much relevance to how much by volume he burns. (Ie... if he has a 50 gallon tank, I really doubt that 1/4 on the gauge will come out to 12.5 gallons.)

On my friends mastercraft, the first 1/4 tank lasts forever and the last half of the tank goes FAST.

[haugy]

The extra 1800lbs, and the fact that you are going to have to run at a higher RPM, and the fact that Carbs if not dialed PRECISELY in can waste a fair bit of fuel......

Yeah, the other boat's going to out run ya in fuel. The fuel injected boats can burn less, not because they are that much more efficient engines, just the fuel delivery system is more accurate. A fuel injected can be the same or worse than a carb'd engine if not maintained properly.

This debate always goes on. But the newer boats were also designed with fuel economy in mind. Hull design, trim tabs, engines, fuel management systems, etc.

And I also agree with Wotan. Are you both running a 30 gallon tank? Because my buddies launch holds twice as much fuel as my Saltare. So yeah, his 1/4 of a tank is going to be more than my 1/4 of tank.

[docdrs]

In my opinion 99 outback 350 carb .....2009 21v 350mpfi cat is way better on gas, and its a bigger boat ,sacked out,and more peeps......I would say at 20- 25% better.......even I cant believe it ... just my experience and opinion

[TitanTn]

Are you both running a 30 gallon tank? Because my buddies launch holds twice as much fuel as my Saltare.

What size is your tank? My Saltare's tank is 50 gallons.

[cadunkle]

Haven't gotten around to measuring fuel on a purely riding day, but on a day of cruising around at 20-22 MPH mostly, with a small amount of idling through no wakes and a few WOT blasts I came out with ~6 GPH in my '89 Saltare with 454 and 800 CFM double pumper.

Interestingly enough this is the same fuel consumption my tow pig gets while towing the Saltare on the highway. Tow pig is a lifted '86 F-350 with 460 and 750 CFM double pumper. Makes sense though, with similar displacement and with those results I'd assume similar load on the engine.

As for carb vs fuel injection... I hate fuel injection. It's the tool of the devil and none of my vehicles are fuel injected. I won't trust it to something that I need to depend on to get to work every day, or depend on to keep me from being stranded in the middle of a shipping channel with tankers, barges, aircraft carriers, and whatnot headed at me. A carb is only as efficient as the person tuning it, and at the end of the day the same goes for fuel injection. Of course certain designs of each will be slightly more or less efficient, but more or less they're all in the same ballpark.

[cadunkle]

What size is your tank? My Saltare's tank is 50 gallons.

I figured 50 gallons from measuring external dimensions but owners manual says 46 gallon I think? Most I've ever put in it was just over 40 gallons, but of course it was still running when I put it back on the trailer...

[DAFF]

How does your boat seem to run?? Rich, smelly or hard starts can be indications the carb is out of wack and might be needing a rebuild. Driving style can also play a factor in fuel consumption. IMO 3/4 of a tank in 4 hrs seems on the high side. 5 gal an hour on fuel.....

[wakeup]

Boats not hard to start if u pump throttle a few times. It is very cold natured . U can't pit it in gear til it's warm or it will cut off. The thing I have noticed is if I let it idle for long periods of time it does seem to load up and will not clear itself out until I run the crap out of it.
Do any of you guys know the stock jet size in your holleys with 351w in them. Checked plugs and they're black in which I know is to rich.

[wakeup]

My tank is 37 gallon.emptied tank the other day with pump and had Ruffly 6 gallons left in it . So that's 31 gallons in 4 hours. Ive had this boat 4 years and nothing has changed except mileage. The boat still runs great. No leaks, same ballast, same lake, gas from same store, yearly tune up. But dam.... Something is causing it. I'm just venting on here guys . So bare with me. Wanna be on water more but it's breaking me.