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Fuel consumption amounts

sashko1

Contributing Member
"Hi all,

could you tell me


"Hi all,

could you tell me what's the approximate difference in fuel consumption is when the Motor is in Neutral (Idling) in comparison to Forward (Throttle Wide Open)? Is it something like: a) not significant, b) twice the amount or c) "man you crazy, -it's x10 times more"!?

Thanks in advance for your support.

Oh, sorry, in case you need this info, outboard motor: Johnson 1970, 2-cycle, 60HP, 3 cylinder."
 
"go over to the mercury outboa

"go over to the mercury outboard,..boards,and ring ol graham lamb....he has an excellent chart."
 
Put brain into gear. does your

Put brain into gear. does your car use the same amount of fuel when idling in neutral as it does when you have the pedal on the floor?
 
"Well, VicS, I guess you need

"Well, VicS, I guess you need to put your <u>eyes</u> "into gear".

I know it's different, the question was to quantify the difference. Pay attention boy!}"
 
From what I can remember from

From what I can remember from the 70HP I owned it was close to 5 gallons per hour at a comfortable cruising speed on a 17ft boat. Wide open add a 2 or 3 more gallons per hour.
 
"I guess it would be nice to k

"I guess it would be nice to know what you mean as far as "fuel consumption"
1. how fast you drain your tank
or
2. how far you can go on a tank of fuel

throttle advance increased the amount of fuel and air introduced to the piston.
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"Well,

let me get back a li


"Well,

let me get back a little bit.
last summer I had and issue with my motor running fine when Idling but once put in gear IN THE WATER (not with ear muffs) the motor would die.

I cleaned everything, replaced ign.coil, checked spark, compression, everything seemed to be fine. Went back to the lake - died again. Note: on ear muffs works fine, I can go Wide Throttle no problem.

Last week I was draining the fuel tank via the existing fuel lines and noticed a smell of gas around aftermarket inline filter. When I touched it some fuel spilled. Looks like it loosened after couple of successful initial boat trips.

So, I was wondering, maybe when I try to put some power on the motor the air gets into the fuel lines and therefore insufficient fuel supply to the cylinders?

How possible is that for my described case?

Thank you all."
 
Re check compression and clean

Re check compression and clean carbs and re-sync. The fuel line you describe shouldn't cause it to stall at idle going into gear.
 
"Oh my God!
Back to the same


"Oh my God!
Back to the same again.... I've done that like 10 times already. I think I can disassemble those carbs (yes, with floats removed, and orifaces blown, etc.) with my eyes closed now.
No, it's not the carbs.

The compression I also verified 3 times with two different compression gauges: 130, 127, 130 - cant beat that!

It couldn't have gone out of sync since it worked like charm couple of first trips. Then out of a sudden, after a prolonged run time (30 mins), it started to happen occasionally.

But the next time I took the boat out, it wouldn't gain any power at all."
 
"Here, I'm hangin in the O

"Here, I'm hangin in the OMC shadows


Below is 3 real life tests of 150 horse outboards on basically the same hull.

The first is a 150 Honda, then a 150 Opti and a 150 XR6 (so 4 stroke, 2 stroke DFI and 2 stroke carb).

Despite all the claims of the mfgs you will note that if you have a 2 speed boat (idle or full throttle) that the new motors guzzle as much as the "old" carb model 2 stroke.

It's a "trolling" speed that the 4 strokes are efficient compared to the others - so if you simply "putt" around your tank of gas will last forever


Sorry I don't have any Ev/Johnson numbers but just for comparitive purposes I have an 1986, 140 looper and from my own "tests" it is comparable to the Opti (floscan shows 14 gph at WOT/5700rpm and 6 gph/3400rpm mounted on my boat - 25'8"/2600lbs rigged) of course my speeds are slower because Honda and Opti were tested with a rigged weight of 1875lbs and the XR6 at 1600lbs (if I'm rememberin' correctly)...

The line in bold is the speed where they get their optimal economy.

375194.jpg

375195.jpg

375196.jpg
"
 
"Run any 2 stroke in a barrel

"Run any 2 stroke in a barrel for even a couple of minutes and then wipe off all the oil crud from the leg and the barrel and look at the floaties in the water. Now fire up the 4 stoke and let it for for an hour...hmm clean water, clean leg, clean barrel."
 
"I loved the HONDA chart.
Max


"I loved the HONDA chart.
Max economy at 1000RPM and 3,9 knots!
Why by a 150 and not a 3 Hp engine?
This is all 'old'.
Go trolling, use a 4-stroke kicker.
Go skiing -nothing like a 2-stroke, DFI or not!
As for oil residue on water/rig:
Where does the oil-change go? Same pollution just another place where you normally do not see it. The biggest polluter is in fact the oil-filter that normally ends up in the bin! The 2-stroke unburnt oil is next to harmless compared."
 
"Morten, you don't recycle

"Morten, you don't recycle old oil and filters down there? You can't dump old oil here. Why dump something that can be cleaned and used again? Oh I forgot, that is the way it has always been done in the past."
 
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