Can your 150hp 4-stroke do this?

[hewesfisher]

This is a real world, on the water, actually on the run shot of my 150hp TWO STROKE's fuel economy. Yes, that reads 6.3mpg, 3380rpm and 28.7mph. Show me yours.

[Toni]

Sure...if I had one.

[MotoBoat]

Hewesfisher, is that wot? If not, what is your top speed at wot?

[BentRod]

Are you sure that's not gallons per mile?
Would think a newer outboard be a little more efficient, but don't have any experience with higher HP outboards let alone 4-strokes.

[Big D]

I might be wrong but I think boat motors run at gallons per hour or GPH.
At least that's what I've been told by folks in the know.

[Amx]

Used to be that way, I don't know about the new stuff, those that are newer than say 2000.

[Jerry H]

My 75 HP Honda gets 4.3 MPG average (run wot on the ocean to where we fish troll then wot back). Gallons per hour may be the correct measure but I find MPG is easier to determine if I'm going to have enough fuel to get home when I'm 30 miles off shore. I always try to figure 1/3 tank out 1/3 tank back and 1/3 tank buffer still in the tank when I get back.

[hewesfisher]

Hewesfisher, is that wot? If not, what is your top speed at wot?

Not even close. IIRC, WOT is 5340rpm and 48mph. It's stored data, so I"ll put that screen shot up later.

Big D, I can produce the GPH numbers too, but MPG makes more sense to me on the water. Besides, if you have instant MPG readout what good is GPH? I did the math on these numbers and it comes out to 4.7GPH.

These numbers are from the '09 Mercury 150hp Optimax on our ProV. Last September we spent 5 days at Rufus Woods and ran from the Cabin by the River to the middle and upper net pens at least once each day (except day of arrival), and took a sight seeing trip almost to Bridgeport one day. My tank holds 48gals, and it was full at the beginning of our stay. My post on our fuel economy is here in the forum somewhere, but I think we ran something like 150+ miles on the water and averaged 5.5mpg. Believe it or not, the best numbers I've seen were 7.1mpg on that same outing. I think speed was 21 or 22mph, too slow for me. I normally run 4000rpm, 33.6mph, and 5.5mpg.

People always wonder why I travel so far once I launch, this is one of the reasons, I get great fuel economy (when I want to ) so I can afford to go places others won't.

My 75 HP Honda gets 4.3 MPG average (run wot on the ocean to where we fish troll then wot back). Gallons per hour may be the correct measure but I find MPG is easier to determine if I'm going to have enough fuel to get home when I'm 30 miles off shore. I always try to figure 1/3 tank out 1/3 tank back and 1/3 tank buffer still in the tank when I get back.

Very wise on the 1/3, 1/3, 1/3 deal. Exactly what the USCG teaches in their boating courses. Just curious, what is your speed at WOT?

I agree with you, MPG is far more useful than GPH. Most all new motors have the ability to display MPG data when tied in with GPS, that's how the computers are able produce such accurate data. I track fuel consumption in the "fuel used" screen on my MercMonitor and it's always within a half gallon of actual when I refuel.

[MotoBoat]

Hewes, did you say O9' 150 Optimax 2-Smoke?

"This is a real world, on the water, actually on the run shot of my 150hp TWO STROKE's fuel economy".

I had assumed, by 09'. All outboard boat motors produced, were 4 stroke. When was the last year, your motor model was produced in a 2-stroke configuration?

[Bodofish]

Lots of 2 cycle outboards still manufactured and by all the big boys.

[MotoBoat]

Lots of 2 cycle outboards still manufactured and by all the big boys.

What? You don't say! I thought there was a slow train, started many years ago, (from the Government) to remove 2 strokes from use? Starting with the inability to buy a knew one. Leaving the used market as the only source of inventory.

Thought the same was true, for 2 stroke dirt bikes.

[Bodofish]

Lots of 2 cycle outboards still manufactured and by all the big boys.

What? You don't say! I thought there was a slow train, started many years ago, (from the Government) to remove 2 strokes from use? Starting with the inability to buy a knew one. Leaving the used market as the only source of inventory.

Thought the same was true, for 2 stroke dirt bikes.

Go have a look at any of the OB manufactures web sites. Lots of direct injected 2 cycles. It's not about the technology, it's about the hydrocarbons.

[G-Man]

Motoboat - the push was to eliminate carbureted 2 stroke motors. With direct injection, the fuel is introduced to the chamber after the ports are sealed so no unburnt fuel makes its way to the environment. Further, the oil now used for two strokes is designed to burn more completely which makes it all the more environmentally friendly. They are as clean or cleaner than 4 cycle motors and are authorized for use on Lake Whatcom.

Hewesfisher - I haven't calibrated the fuel metering on my 115HP Etec so I am not certain that the MPG reading I get is accurate. I do adjust RPMs and trim out my motor to maximize fuel economy which is typically around 5.5MPG while cruising at 28MPH. That being said, my economy goes up and down depending upon how much weight I'm carrying around with me. I'm sure I could bring up that number if I'd go without a spare anchor, spare battery, several extra downrigger weights and a full tackle shop of gear. What I can say for certain is that a full gas tank of 46 gallons lasts me a good long time.

[Bodofish]

Motoboat - the push was to eliminate carbureted 2 stroke motors. With direct injection, the fuel is introduced to the chamber after the ports are sealed so no unburnt fuel makes its way to the environment. Further, the oil now used for two strokes is designed to burn more completely which makes it all the more environmentally friendly. They are as clean or cleaner than 4 cycle motors and are authorized for use on Lake Whatcom.

Hewesfisher - I haven't calibrated the fuel metering on my 115HP Etec so I am not certain that the MPG reading I get is accurate. I do adjust RPMs and trim out my motor to maximize fuel economy which is typically around 5.5MPG while cruising at 28MPH. That being said, my economy goes up and down depending upon how much weight I'm carrying around with me. I'm sure I could bring up that number if I'd go without a spare anchor, spare battery, several extra downrigger weights and a full tackle shop of gear. What I can say for certain is that a full gas tank of 46 gallons lasts me a good long time.

I'm going to have to roll with that too. Even with an inboard jet! I filled it up in April and put gas in again in Sept. I must admit most of the time it's kicker moving the boat or I'm anchored casting.

PS: I don't know about MPG, never calculated it but I have GPH and it averages 6GPH with best being 4.2 and worst being 12.... Hammer down white water. Normal cruise at 34 mph GPS

[hewesfisher]

Hewes, did you say O9' 150 Optimax 2-Smoke?

"This is a real world, on the water, actually on the run shot of my 150hp TWO STROKE's fuel economy".

I had assumed, by 09'. All outboard boat motors produced, were 4 stroke. When was the last year, your motor model was produced in a 2-stroke configuration?

Yep, but you can't see any smoke or smell it with the Optimax either. The Optimax is still in production and will be for some time to come. Like G-Man said, the hi-tech 2-strokes are as clean, or cleaner, than comparable 4-strokes. Still lighter and still have the 2-stroke performance. Best of both worlds.

G-Man - I don't have to do any calibrating, my MercMonitor was simply "plug and play" and I really enjoy having instant MPG readouts along with many other important, motor specific features, such as water pressure, temperature, etc. One interesting thing I learned about my setup after installing the MercMonitor, the method I was taught to set for optimum trim, set speed, trim out until just porpoising, then trim in just until it stops, was not the optimum. At what I estimated to be my best economy trim/rpm setting was actually not. I have to run more trim in than I would have without the digital display, but the computer doesn't lie. I really appreciate it when it comes time to refuel, my "fuel used" display is always within a half gallon of what it takes to fill the tank. That's real accurate.

My performance numbers shown above are on a fully loaded boat, full tank of fuel, 3 batteries (one of which is the monster Sears PM-1 that weighs 75lbs), tackle, gear, cooler with ice, kicker, and two people on board. My boat weighs 3600lbs as loaded less trailer weight of 718lbs, plus 290lbs for my wife and I, and that puts the on the water weight at 3172lbs. That's pretty darn good economy out of a 150hp 2-stroke if you ask me, and real deep into the supposed 4-stroke economy advantage. Although, I hear the new Merc 150hp, 3liter, 4-stroke is very close to the Opti in overall performance and fuel economy.

[Jerry H]

Hewesfisher: Not sure how to do the quote thing so here is the answer to your question - Just curious, what is your speed at WOT?

I have a 75 HP Honda on an Arima. I have two props one that I don't run often (came with the boat from the dealer I use it as a back up) Way too much pitch, poor overall performance and economy until you finally get it on plain then it runs 38 to 41 MPH at 5200 RPM. The prop I normally run pushes us at 31 MPH at 5600 RPM. It lets the motor get into the power band sooner, better bottom end starts and performance so I can live with the lost top end.

[Amx]

Hewesfisher: Not sure how to do the quote thing so here is the answer to your question - Just curious, what is your speed at WOT?

I have a 75 HP Honda on an Arima. I have two props one that I don't run often (came with the boat from the dealer I use it as a back up) Way too much pitch, poor overall performance and economy until you finally get it on plain then it runs 38 to 41 MPH at 5200 RPM. The prop I normally run pushes us at 31 MPH at 5600 RPM. It lets the motor get into the power band sooner, better bottom end starts and performance so I can live with the lost top end.

click on the quote button at the top right of each post.

Looks like you need a prop half way between the 2 that you have. What is the factory recomended max rpm of your engine?