'72 1150 merc. Fuel consumption?

Bwalker

Petty Officer 1st Class
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Jun 13, 2005
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I recently purchased a 16' glastron Runabout/bowrider with this type motor on it. My question is with the amount of fuel I burned off! I know it's hard to give me advice due to so many variables. Also, I don't know what would determine good or bad fuel "mileage" would it be calculated by "miles" or by "hours" run. I had less than desirable conditions with some small Whitecaps, I logged about 25 mi. sometimes running a distance of about 6-8 mi @ 37-38 mph @ 3700-4000 rpm's. This consumed 5 1/2 gal. Wasn't much fun time for the cost!!
 

kenmyfam

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Aug 10, 2006
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Re: '72 1150 merc. Fuel consumption?

Were you running WOT ??? All depends on how much load, RPM, fighting the current or going with it ?? If you were at 2 third throttle and cruising then this is bad. If you were running wide open then maybe !!
 

kenmyfam

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Re: '72 1150 merc. Fuel consumption?

Forgot to mention, my 16 ft Doral with 4 people on board a 140 hp Johnson and cruising at about 30 to 35 mph gets about 2.7 to 3.0 mpg gauged by gps and amount of fuel to refill again.
Hope this helps.
 

Bwalker

Petty Officer 1st Class
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Re: '72 1150 merc. Fuel consumption?

Yes, it definitely helps! This is my first boat and I have no clue to somethings like this. I had a moderate load, I'd say 325 lbs 2/3 throttle @ about 38 mph and choppy water. Also, this sounds close because I calculated the distance and it came out to 23 mi. or per the 5 gal. used about 4 mpg. Thanks PS. I thought it should get about 15 mpg or at least thats what i wish it would get
 

Solittle

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Apr 28, 2002
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Re: '72 1150 merc. Fuel consumption?

The "general" rule of thumb is 10% of the hp in gal per hour at wide open throttle. So a 115 "should" burn 11.5 gal in an hour at WOT. Back it off a bit and you will do lots better.

I don't figgure gal. per hr. or miles per gal. I figgure $ of fuel per fun day. Using that if I burn 25 gal in a day at $3.00 per gallon - thats about $75.00. That gets me and my family + one or two extras (maybe 5-6 people) a fun day on the water. Try taking our 5-6 people to the movies and dinner at a family resturant - - $75.00 won't come close.
 

kenmyfam

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Re: '72 1150 merc. Fuel consumption?

Bwalker said:
Yes, it definitely helps! This is my first boat and I have no clue to somethings like this. I had a moderate load, I'd say 325 lbs 2/3 throttle @ about 38 mph and choppy water. Also, this sounds close because I calculated the distance and it came out to 23 mi. or per the 5 gal. used about 4 mpg. Thanks PS. I thought it should get about 15 mpg or at least thats what i wish it would get
Seems you are about right then !!
With my boat I would have to paddle 12 miles of the 15 to get that gas mileage !!! LOL
 

monk-monk

Chief Petty Officer
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Aug 27, 2006
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Re: '72 1150 merc. Fuel consumption?

This thread was actually started by Username monk-monk. Believe it or not, I left iboats program running all day on my computor and came in posted this thead, came back to check responses and found it listed by bwalker. The reason I clarify this is for further threads regarding this. I have no idea how this occured! By-the-way kenmyfam..I got a great laugh outta that one
 

Plainsman

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Apr 2, 2006
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Re: '72 1150 merc. Fuel consumption?

Got it out in the water monk-monk!! Great to hear!

What size prop do you have on it?
 

kenmyfam

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Re: '72 1150 merc. Fuel consumption?

monk-monk said:
This thread was actually started by Username monk-monk. Believe it or not, I left iboats program running all day on my computor and came in posted this thead, came back to check responses and found it listed by bwalker. The reason I clarify this is for further threads regarding this. I have no idea how this occured! By-the-way kenmyfam..I got a great laugh outta that one
Either that or install a mast and sail !!
 

monk-monk

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Aug 27, 2006
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Re: '72 1150 merc. Fuel consumption?

[whisper uid=72356]

Enter private whisper here

[/whisper] yes Eric I finally got it in the water!! It runs pretty good...I'm really happy w/ it. I still have tuning issues I need to work on. I have to idle it @ about 800 rpm's to put it in gear or it wants to stall out. Also, when I put it in gear and throttle-up, it seems like it could be "loaded-up" for it seems like it wants to be cleared out, and after i get cruising at steady throttle, it automatically increases rpm's w/ out any throttle movement at the helm and then the rpm's will stay steady. Over-all I love it and will continue to learn about this motor
 

Plainsman

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Re: '72 1150 merc. Fuel consumption?

Hi Ed,

Mine idles around 800 too, I don't think that is a problem as long as your under 1000 (bad). I also have the same problem with the speed increase. I get no power until I get the throttle to about 9AM. If I leave it there, it picks up speed on its own. I get about 38 mph for WOT with a 19 in prop.
 

phatmanmike

Captain
Joined
Oct 24, 2003
Messages
3,869
Re: '72 1150 merc. Fuel consumption?

old inline mercs dont run on the "standard rule" they drink fuel like no tommorrow. either get used to it or get a different motor.

my last inline was a 1976 1150, mounted on a 16 foot center console with very small draft. our best was 1.5 mpg. usually wed get less than that.

wed go through 2 full 6 gall tanks in less than one hour, much less.

very famous for drinking fuel!
 

phatmanmike

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Oct 24, 2003
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3,869
Re: '72 1150 merc. Fuel consumption?

Bwalker said:
Thanks PS. I thought it should get about 15 mpg or at least thats what i wish it would get


wow, thats a good one! 15mpg in a boat? maybe a diesle, at idle, being towed, with the wind, downhill
 

monk-monk

Chief Petty Officer
Joined
Aug 27, 2006
Messages
642
Re: '72 1150 merc. Fuel consumption?

dam guys! That info makes me feel good because I'm getting some good fuel milage then. Now I realize...this motor drinks fuel...for fun...it cost .65 cents a gallon when they built it..it now costs nearly $ 3.00 a gallon and I ain't gettin' 15 MPG until Niagra Falls becomes the Main channel
 

kenmyfam

Supreme Mariner
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14,392
Re: '72 1150 merc. Fuel consumption?

monk-monk said:
dam guys! That info makes me feel good because I'm getting some good fuel milage then. Now I realize...this motor drinks fuel...for fun...it cost .65 cents a gallon when they built it..it now costs nearly $ 3.00 a gallon and I ain't gettin' 15 MPG until Niagra Falls becomes the Main channel
You also may get close to 15 mpg when you are towing it on the trailer.....that is.....depending on your tow vehicle ! LOL
 
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