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| 5.7 Gi 280HP 1997 on Vista 256 https://www.smwebhead.com/phpBB3/viewtopic.php?f=6&t=23457 |
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| Author: | Slunchev [ Tue Aug 27, 2019 11:27 pm ] |
| Post subject: | 5.7 Gi 280HP 1997 on Vista 256 |
Hi guys, I have a fuel consumption on my boat. Is it some one have an similar engine and can share what is the consumption in cruise speed / RPM? I have 3500RPM with 25 knots and my consumption is 60 liters/hour. Original the engine was with injection system but the previous owner change with carburetor. Thanks in advance to all. |
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| Author: | LouC [ Wed Aug 28, 2019 7:10 am ] |
| Post subject: | Re: 5.7 Gi 280HP 1997 on Vista 256 |
That’s close to 16 gallons per hour...I think my little H200 with the 4.3 V6 uses about 7-10 gallons per hr at the same rpm...esp if I keep it at the point before the secondaries in the 4 bbl carb open..you have a big heavy boat being pushed by a single gas 5.7 engine which is working hard to move all that weight and if the carb is adjusted properly that may be the best it can do. More info is needed...what brand of carb...2 or 4 bbl...if it’s a Holley 4 bbl they are known to use a lot of fuel esp once the vacuum secondaries open...the more sophisticated Quadrajet 4bbl is better on fuel, that’s what mine has...post a pic of which carb is on your engine. |
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| Author: | njboater [ Thu Aug 29, 2019 6:19 am ] |
| Post subject: | Re: 5.7 Gi 280HP 1997 on Vista 256 |
If not already posted, this has some good fuel flow information: https://www.fourwinns.com/uploads/2017/ ... 2016V6.pdf I got my VesselView and Mercmonitor setup on my 6.2l and found I use 22 GPS at WOT. At 4000 RPM and about 25knots Im doing 11-12 gps. njboater |
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| Author: | babbot1 [ Thu Aug 29, 2019 7:38 am ] |
| Post subject: | Re: 5.7 Gi 280HP 1997 on Vista 256 |
My previous 258 with 5.7gi duo props got about 10gal/hr at 3500rpm cruise at 27mph. This was an estimate from fill up to fill up and was pretty close to the four winns fast facts. It was a very efficient engine combo in my opinion. Is that a dual prop setup? That also makes a big difference on efficiency. If you have a carb and single prop then that number doesn't sounds out of sight. |
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| Author: | Slunchev [ Mon Sep 02, 2019 10:49 pm ] |
| Post subject: | Re: 5.7 Gi 280HP 1997 on Vista 256 |
Hi guys, Thank you for your respond. The motor originals is designed with mono injectors system. But the previous owner replaced with 2 Jet Rochester carburetor. 2bbl The 3 blades single propeller. Yesterday I changed with 4 blades but the result is worse- the motor reached 3000 RPM in 15 Knots and that's all.... |
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| Author: | babbot1 [ Tue Sep 03, 2019 6:47 am ] |
| Post subject: | Re: 5.7 Gi 280HP 1997 on Vista 256 |
4 blade will work better but you have to get the correct pitch. Usually you drop 1-2" pitch going from 3 blade to 4 blade without any changes to engine speed. Then if you went aluminum to stainless or vice versa there is also a change. Check the Four Winns fast facts for the original prop pitch that came with the boat as a starting point. If you originally had the correct one and only hit 3500 then there's something else wrong. Having 2 carbs you're going to need to tune them correctly together or else you will have adverse effects. Start with the basics and make sure all your ignition components are good, new spark plugs, wires, cap/rotor. Then tune the carbs. |
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| Author: | LouC [ Tue Sep 03, 2019 8:33 am ] |
| Post subject: | Re: 5.7 Gi 280HP 1997 on Vista 256 |
Slunchev wrote: Hi guys, Thank you for your respond. The motor originals is designed with mono injectors system. But the previous owner replaced with 2 Jet Rochester carburetor. 2bbl The 3 blades single propeller. Yesterday I changed with 4 blades but the result is worse- the motor reached 3000 RPM in 15 Knots and that's all.... They should have installed a spread bore manifold and used a Holley 4175 or a square bore Edelbrock marine intake with either an Edelbrock 1409 or Holley 4160. Even with the restrictive little 2 bbl. 4400-4600 rpm wide open.... |
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