Merc v6 Fuel Consumption

[MackAttack]

Any help on comparing fuel consumption between carb and EFI motoros? I have hear dthat the EFI actualy uses MORE fule than the carb motor. Can this be true?<br /><br />I am looking at 2 boats, same boat (30' Scarab Sport) with the following engine package:<br />... a) twin 1994 225 carb motors<br />... b) twin 1997 250 EFI motors<br /><br />Any input/advice will be much appreciated!

 

[KCLOST]

Re: Merc v6 Fuel Consumption

I've heard that a "basic" formula to determine fuel usage per hout at WOT...<br /><br />Is the hp/10=fuel usage per hour..<br /><br />225/10 = 22.5 gallons per hour at WOT<br /><br />But for an EFI, I'm not sure...

 

[LubeDude]

Re: Merc v6 Fuel Consumption

KC, Check your decimal points, I think its more like 2.5 Gallons per hour. If it were 22.5, I think we should sell our boats. <br /><br />On another post I seem to have heard that the fuel consumption on a merc 150 was in the neighborhood of 4,5 per hour at WOT, and 2.5 at cruising speed. I really do not know for sure. I do know that I can go through 10 gallons of fuel in a day of Bass Fishing if the bite is slow.

 

[KCLOST]

Re: Merc v6 Fuel Consumption

Oooops...<br /><br />I really don't know how accurate that formula is even with a 100 divider... Sorry for the error...

 

[MackAttack]

Re: Merc v6 Fuel Consumption

22.5 GPH is probably right for KCLOST.<br /><br />My big boat (25' w/ 370hp 454) uses about 28gph @ WOT. It uses 10gph @ 24mph = 2.4mpg at its most efficient cruise speed.<br /><br />I do appreciate the comments, and hope to fin out whihc is actually the best (reliability wise) and most fuel efficient (70 miles to Gulf Stream here).<br /><br />KCLOST - where do you liv ein KC? I grew up there, and family still lives there.

 

[KCLOST]

Re: Merc v6 Fuel Consumption

Ha,Ha, Lube!!!!!<br /><br />Mack, I'm around the Liberty area... But have lived on the Kansas side also (Overland Park) in the past....

 

[MackAttack]

Re: Merc v6 Fuel Consumption

LubeDude ... I'm not trying to say you're wrong - Bass boats are defintely more efficient than my 26'er/454, and I really appreciate any/all insight!<br /><br />KCLOST - where do you fish? My father fishes @ Truman (hes there today in fact), and we grew up fishing on Pomme De Terre, which seems to have slowed now.<br /><br />Thanks again guys!

 

[LubeDude]

Re: Merc v6 Fuel Consumption

I do not think I am wrong, (have been before though), There is BIG difference in a 2.4 liter V6 and a 454, Like three times bigger! and a bigger boat, and a, and a, and!!!<br /><br />If my engine burned anywhere near 22 Gal per hour, I couldnt even get from one end of the lake to the other on a tank of gas.

 

[KCLOST]

Re: Merc v6 Fuel Consumption

I'm just kiddin ya Lube, I really have no idea if that formula is correct for all ranges of hp or not....<br /><br />Mack, I mainly fish Smithville, Truman, Hillsdale and Bull Shoals (parents live there).... Bass Fishing has been pretty slow at Smithville the last few years and I haven't had a chance to fish the others yet this spring. But having fun anyway...

 

[AndyL]

Re: Merc v6 Fuel Consumption

I reckon KCLOST is not far off with his original calculations. My 135 did 2 miles to the gallon and my new 150 (Carbed) is about the same.That would equate on my boat to about 16 gall/hour at WOT. The cost of fuel is a major consideration when boating any distance as we are paying up to £0.80/Litre here.About $5 gallon in your terms. The only good thing is it is a boat you are pushing and no push equals no fish.<br />I have heard the new Evinrude Fichts are incredibly lean on gas but at least with Carbs you can fault find easier and get to most bits without specialized tools.<br />We are all hoping the latest Gulf problems don't escalate the price much higher as one day the wife will find out the handbag has emptied.

 

[wilde1j]

Re: Merc v6 Fuel Consumption

KCLOST is correct, HP/10~GPH @ WOT. 2.5 GPH is nowhere near close to a 225's fuel consumption. I have twin 150's and they clearly burn ~ 15 GPH each at WOT according to Floscan. This relationship holds approximately for estimating WOT fuel consumption of all two stroke motors (except DI's of course).<br /><br />Sorry, Lube, you must run on a small lake.

 

[KCLOST]

Re: Merc v6 Fuel Consumption

 

[LubeDude]

Re: Merc v6 Fuel Consumption

Like I said, (Ive been wrong before).<br /><br />A while back, I took the misses and we spent the day on two different lakes, We spent maybe four hours on the water at some WOT, and mostly 25 MPH cruise speed. I toped off on the way home and put in just over 10 Gals. Where I went to school, that works out to 2.5 Gals. per hour. Thats a long ways from 10-15 Gals per hour.<br /><br />Im sure it makes a big diffrence on the size of your boat and the efficiency of your hull, I believe that the Smart Tabs make my boat a lot more efficient also. I know for a fact that I do not need as much RPM to maintain a slow plane.

 

[Paul Moir]

Re: Merc v6 Fuel Consumption

It seems to me the DI engines and four-strokes are in the 7.5%-9% range for WOT. A new DI Bombardier 250 for an example consumes around 23 gal/hr at WOT according to their website.<br /><br />'Course, there's a huge difference in fuel consumption between cruising speed and WOT. Under half the consumption rate in some cases.

 

[MackAttack]

Re: Merc v6 Fuel Consumption

Ok - so back to my question (need help before I buy another boat tomorrow).<br /><br />1994 225 Carb Mercury motors or<br />1997 250 EFI Mercury motors <br /><br />?????????????????????<br /><br />Any idea where to get specifictions on Merc OBs? Also where do I get performance/fuel consumptions info?<br /><br />Thnx again ....

 

[gss036]

Re: Merc v6 Fuel Consumption

I have heard that the 250's are gas hogs. But , if I were in your shoes I would going with the 250 EFI's for a 30 foot boat.<br />I run a single Merc 200 Carb on my SeaCraft 23WA and cruising about 4200-4400 RPM (32-34mph) I consume about 10-12 gals an hour. On saltwater there are lot of varibles for tides and wind/ chop and swell height. WOT I would comsume at least 16 gal per hour. <br />Even the new 200-250 4 strokers are up around 18-22 gal per hr on WOT. Not nearly as efficent as the claims about them. Laws of energy tells you that you need so much fuel to produce so much energy (HP).<br />Sorry LubeDude,I don't buy into your new math theory.

 

[trumanlake]

Re: Merc v6 Fuel Consumption

kclost, i only have a 24 gal tank and @ wot i can use that up in no time at all. if i had to guess i would say somewhere in the neighborhood of 12-15 gal/hr. trying to break the habit of massing the hot foot to the floor!

 

[LubeDude]

Re: Merc v6 Fuel Consumption

Originally posted by LubeDude:<br /> Like I said, (Ive been wrong before).<br /><br />Im sure it makes a big diffrence on the size of your boat and the efficiency of your hull, I believe that the Smart Tabs make my boat a lot more efficient also. I know for a fact that I do not need as much RPM to maintain a slow plane.

I quess I have to concead, but I still say that I only used a little over 10 gallons that day, maybe I never ran as long as I thought I did.

 

[achris]

Re: Merc v6 Fuel Consumption

Hi y'all,<br /><br />Sorry, Lube. At OMC school we were given the formula hp/10=gph at WOT. Obviously the consumption will be less at less than WOT. The way I work it out is to get mpg at WOT, then use that figure for speeds other than WOT. <br /><br />eg, if 250 hp @ WOT gives 50mph. Therefore gets 2mpg. So at 20mph will use 10 gph. I don't know what your boat tops out at, but by the figures (at 25mph for 4 hours, that's 100miles, for 10 gals, that gives 10 mpg) I'd guess at something around 70 mph? How close am I?<br /><br />As for the original question. I'd take an EFI engine over carbs. EFI is generallly better on fuel and also that's the one with the higher power, so you'll not be pushing the engine as hard. Longer life, better fuel use, less wear and tear, you get the picture...<br /><br />Chris.................

 

[AndyL]

Re: Merc v6 Fuel Consumption

Just to throw another angle at it I seem to use the same fuel per mile at 7 knots as I do at 23 knots (Merc 150 Carbs). I often fish with a mate whose boat only does 7 knots (Diesel) and fishing the same mark but getting there at different speeds makes very little difference to the fuel consumption over the day.