Bad fuel mileage

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tripper1112
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Bad fuel mileage

Post by tripper1112 » Fri Jul 12, 2013 2:02 pm

Iam running a 383 stroker with edelbrock 170 e-tec heads,1407 edelbrock 4 barrel carb,2.55 stinger gearbox,80" 3 blade Falcon series prop on a 13'6"x7' Diamondback sled w/poly running at 5400 rpm wot and it seems like i am burning to much fuel.I ran approx. 70 miles and burned about 30 gallons does this sound right? I also have some dieseling when i shut down the motor.I am wondering if my timing is off a little bit could this be causing these problems.Any help is greatly appreciated! :scratch: :scratch: :proud: thanks
Southern Traditions Fulltrack,427 Ford side oiler,T-16 s.p.a.t. differential
04Diamondback 13'x6' full deck 383 stroker,2:55 stinger

loudmouse
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Re: Bad fuel mileage

Post by loudmouse » Fri Jul 12, 2013 3:16 pm

If u suspect the timing is off check it. Check idle timing and wot timing and at what rpm you reach full advance. When timing is correct check AFR. When those two are right ur engine will run smoother, more responsive and cooler.
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14'X8' JW, Chevrolet 122CID LNF Turbo Engine, Ox box, 80" NGR 3 blade

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skinny99
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Re: Bad fuel mileage

Post by skinny99 » Fri Jul 12, 2013 4:35 pm

Fuel mileage can be greatly affected by your boat setup,how heavy you are loaded and how fast/how you drive your boat.
But for reference my old boat got right around 2.5 miles per gallon. It was kinda heavy and had a 383/2.68/R series combo. I liked to
dog it a little and there was usually a little dry running included in that figure.

I rode with other boats that were power by C/M's and were of similar size and they were usually closer to 3 miles per gallon.

So your boat is not that far off however it may be able to be tweaked and get quite a bit better without hurting performance. Some changes may even make it run better everywhere.How free does it ride in the water? Where is the spray out the sides at cruising speeds when loaded like you normally run? Have you done a plug check at typical cruising RPM's? Just because it is tuned correctly at WOT does not mean that it is not overly rich at cruise RPM's.

As far as timing goes. WOT timing is critical in making sure that you do not hurt your engine and allowing it to run to it's full potential.
However as far as fuel mileage goes more is usually better(especially at lighter loads), so I do not believe that if you have slightly more timing (dieseling can be an indicator of excessive timing) that it is causing a decrease in economy.
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flying fish
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Re: Bad fuel mileage

Post by flying fish » Fri Jul 12, 2013 4:49 pm

tripper1112 wrote:Iam running a 383 stroker with edelbrock 170 e-tec heads,1407 edelbrock 4 barrel carb,2.55 stinger gearbox,80" 3 blade Falcon series prop on a 13'6"x7' Diamondback sled w/poly running at 5400 rpm wot and it seems like i am burning to much fuel.I ran approx. 70 miles and burned about 30 gallons does this sound right? I also have some dieseling when i shut down the motor.I am wondering if my timing is off a little bit could this be causing these problems.Any help is greatly appreciated! :scratch: :scratch: :proud: thanks

I would be talking to Plumcrazy or Andrew w/Waterwalker and be trying to get my hands on an 80" 3 blade wide prop in the correct rotation needed. My guess is a Maximus with your given ratio #.

Amazing what you might learn with your setup and a wide prop. ?? just a thought.

I think your hub would yield a 82" Maximus. Still, I wonder about your gear ratio coupled to your exact blades and also your propellers tip speed at cruise and WOT. I am quite familiar with your Falcon blades. :)
15' DB - 6.2 LSA - 4 blade 82" R - 2.52 CH-4

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Deano
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Re: Bad fuel mileage

Post by Deano » Fri Jul 12, 2013 5:15 pm

flying fish wrote:I would be talking to Plumcrazy or Andrew w/Waterwalker and be trying to get my hands on an 80" 3 blade wide prop in the correct rotation needed. My guess is a Maximus with your given ratio #.
Amazing what you might learn with your setup and a wide prop. ?? just a thought.
I think your hub would yield a 82" Maximus. Still, I wonder about your gear ratio coupled to your exact blades and also your propellers tip speed at cruise and WOT. I am quite familiar with your Falcon blades. :)
This is information to take to the bank.
It's a wonder you got as good mileage as you did given that prop with that gear. Shows how versatile those Falcons are !
Given your ratio, if your engine is wanting to turn 5400, those Maximus blades would be right at their sweet spot and very likely as economical as you're going to get. :)
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