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Fuel burn for mercury 115 2 stroke saltwater series 2002?

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Fuel burn for mercury 115 2 stroke saltwater series 2002?

Old 02-11-2019, 07:08 PM
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Default Fuel burn for mercury 115 2 stroke saltwater series 2002?

Anyone know where to get figures for one of these engine in terms of fuel consumption? Would like to see results from test boats etc if possible. I have searched online and only seem to get info on optimax and 4 stroke engines. Im looking at a mercury 2 stroke saltwater series from 2002.

This page is great but mainly deals with four strokes Mercury efi 25 - 40 - 50 - 75 - 90 - 115 - 150 - 175 - 200 - 225 - 250 - 350 hp SCi Verado Outboard Fuel Consumption Liters per hour | Portable 3.5 - 4 - 6 - 8 - 9.9 - 15 hp

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Old 02-11-2019, 07:19 PM
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Ruff rule of thumb for a four stroke motor is the rated HP times 10% translates to gallons per hour.

Figure 11.5 gallons per hour at WOT when propped to the upper end of the RPM range.

Now since you are asking about a two stroke, and a Mercury at that, and they are both known to be thirsty, maybe add a couple for gallons per hour.
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Old 02-12-2019, 07:20 AM
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Figure 7.5 GPH at a 4K cruise RPM and then be pleasantly surprised if it's less. Good motor
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Old 02-12-2019, 09:32 AM
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Originally Posted by Fatjoe View Post
Anyone know where to get figures for one of these engine in terms of fuel consumption? Would like to see results from test boats etc if possible. I have searched online and only seem to get info on optimax and 4 stroke engines. Im looking at a mercury 2 stroke saltwater series from 2002.

This page is great but mainly deals with four strokes Mercury efi 25 - 40 - 50 - 75 - 90 - 115 - 150 - 175 - 200 - 225 - 250 - 350 hp SCi Verado Outboard Fuel Consumption Liters per hour | Portable 3.5 - 4 - 6 - 8 - 9.9 - 15 hp
That page also has Optimax on a separate tab on the top, I find it pretty accurate for my Suzuki. I'm surprised it says a 115 Optimax only burns 9.9 GPH at WOT, less than the 4 stroke Merc or my Suzuki.

Really looking at the fuel burn across the range either the Opti is amazingly more efficient than I thought or the site is wrong.
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Old 02-12-2019, 09:47 AM
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I think the 7.5gph at 4k is a pretty good guess. Might be a little more. Plan on 10gph for trip planning, and then measure actual burn.
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Old 02-12-2019, 10:04 AM
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Originally Posted by VTXrider View Post
That page also has Optimax on a separate tab on the top, I find it pretty accurate for my Suzuki. I'm surprised it says a 115 Optimax only burns 9.9 GPH at WOT, less than the 4 stroke Merc or my Suzuki.

Really looking at the fuel burn across the range either the Opti is amazingly more efficient than I thought or the site is wrong.
Discounting the G2 wonder motors Opti's have long been the most efficient engines available to us. Any web based info could only be averages at best and if associated with the manufacture then count on some embellishment. And any motor can exhibit significantly different burn rates relative to propping and loading - a 115 anything on a light flats skiff and slightly underpropped will exhibit substantially better burn rates than one propped to the bottom of the range and pushing a 20' Mako.
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Old 02-12-2019, 11:24 AM
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Originally Posted by HTJ View Post
Discounting the G2 wonder motors Opti's have long been the most efficient engines available to us. Any web based info could only be averages at best and if associated with the manufacture then count on some embellishment. And any motor can exhibit significantly different burn rates relative to propping and loading - a 115 anything on a light flats skiff and slightly underpropped will exhibit substantially better burn rates than one propped to the bottom of the range and pushing a 20' Mako.
I can see that, I was assuming propped to hit the top of the WOT range as the fuel burn numbers do on my Suzuki 115 but now that you mention it that is my assumption based on nothing. So who knows what variables are involved in these numbers.

I knew Opti's are known to be very efficient but if the numbers are propped reasonably, I'm still amazed by the numbers given. As you say they could be fudged a bit.
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Old 02-12-2019, 07:13 PM
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Originally Posted by HTJ View Post
Figure 7.5 GPH at a 4K cruise RPM and then be pleasantly surprised if it's less. Good motor
Thanks. Looking thirsty compared to the figures I have found for the Yamaha f115 that supposedly does 4. 8 GPH (found these figures here: Yamaha F 25 - 50 - 70 - 90 - 115 - 150 - 175A - 200 - 225 - 250 - 300 - 350 hp Outboard Fuel Consumption chart GPH MPG Test & Specs | Portable F 4 - 5 - 6 - 8 - 9.9 - 15 - 20 hp)
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Old 02-12-2019, 07:38 PM
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Originally Posted by VTXrider View Post
I can see that, I was assuming propped to hit the top of the WOT range as the fuel burn numbers do on my Suzuki 115 but now that you mention it that is my assumption based on nothing. So who knows what variables are involved in these numbers.

I knew Opti's are known to be very efficient but if the numbers are propped reasonably, I'm still amazed by the numbers given. As you say they could be fudged a bit.
Fudged and/or different conditions on test days, operator A better at trimming/running the boat than operator B, wind/current, fuel flow meter off a bit etc, etc - tons of variables and 1% error rate here and there can add up to skewed data.
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