# Fuel economy question



## Seth (Mar 25, 2009)

Does it make much of a difference in fuel economy when you go from say a 90/65 up to a 150/105 or bigger? My buddy said that anything over a 90/65 will kill your fuel economy, even on the newer Etec's and Optimax's.

I don't think Im getting very good fuel economy out of my older 2 stroke 50hp Yamaha anyways so it probably wouldn't be enough to matter to me but I was just curious.


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## Quackrstackr (Mar 25, 2009)

My 90 gets about the same as the 115 that was on my old boat.

None of the carbureted engines get good mileage. Of course, just how bad depends a bit on whether you are talking a 50 or a 250. There is a change in mileage given the same hp when you go injected 2 stroke (opti or etech) and another when you go 4 stroke

My 90 sips fuel at 3/4 throttle compared to what it guzzles down at wot.


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## Toby from MO (Mar 25, 2009)

Seth said:


> Does it make much of a difference in fuel economy when you go from say a 90/65 up to a 150/105 or bigger? My buddy said that anything over a 90/65 will kill your fuel economy, even on the newer Etec's and Optimax's.
> 
> I don't think Im getting very good fuel economy out of my older 2 stroke 50hp Yamaha anyways so it probably wouldn't be enough to matter to me but I was just curious.



This is a tough question because if you’re interested in the best fuel consumption you must accurately match motor size to the boat and/or load you intend on pushing. I would always choose the most HP you can…what your boat is rated for. Though a slightly larger engine may burn more fuel it will not work nearly as hard as the smaller motor.

I’ll also tell you (within some limits) that a local boat dealer will get your custom built aluminum hull badged with whatever HP rating you want…that is if he thinks he can sell you a bigger motor. 

There is no doubt…assuming you are comparing engines with similar ignition & fuel control systems the larger engine will burn more fuel than a smaller engine. Engine HP output is the direct result of the size/energy of the air/fuel combustion occurring…bigger volume, bigger combustion =’s bigger air intake/exhaust and more fuel burned. 

Comparing older carbureted 2-stroke vs newer 2-stroke or 4-stroke w/computer controlled fuel injection. No question the fuel injected will burn less than the carbureted. I’d say this may be true even with rather large HP differences…i.e. carbureted 50hp vs. fuel injected 90. 

You should consider that multiple HP offerings from the same manufacture may utilize the same power head. For example, 40 - 60 may be the same power head…75 – 115 may be another…135 – 175 another…200 – 250 another…so on so forth. Within each family, though the larger will burn more fuel, the fuel usage (gallons/hr) will be relatively close.

This why in the other thread I recommended the smaller 56” width given your motor choice. A 150hp on a 56” bottom is ideal….good speed and fuel consumption. If you are leaning towards the 90 then I would consider a 52” bottom width. I rarely see 60” boats…unless given special need.

For what ever reason my 96 model 1852 was only rated for a 50hp. I was so close to swapping the badge for a 90hp, or even a 150hp, badge but this got a little “iffy” finding a manufacturer to do it. So I chose to stay within the limits Johnny Law has set for me and went with the 60/40.


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## Toby from MO (Mar 25, 2009)

Quackrstackr said:


> My 90 sips fuel at 3/4 throttle compared to what it guzzles down at wot.



This is the best advice yet. Mine runs wot at about 5200rpm. After on plane...I throttle down to about 4600-4700rpm. I only lose about 1-2 mph but it cuts fuel consumption significantly.


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## redbug (Mar 25, 2009)

it's not a jet, but my yammay 225 does much better on fuel than my 175 yammy did But like others have stated I'm runnung at lower rpms to get the same speed


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## bassboy1 (Mar 25, 2009)

If you are looking for fuel economy alone, a jet is not the way to go.....


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## Toby from MO (Mar 26, 2009)

bassboy1 said:


> If you are looking for fuel economy alone, a jet is not the way to go.....



You can say that again….though, for me, the jet is my only option given the water I play in.

Not to recommend one thing over another I will describe my choices/experiences for comparison sake.

This past summer I replaced a carbureted 40/28 2-stroke with a fuel injected 60/40 4-stroke. I was originally very concerned about the torque loss with a 4-stroke vs. 2-stroke…though I was able to get my 4-stroke for some $1200 - $1500 less than the same sized Etec. In this case the money differences overcome my concerns. After a full summer of use I could not be happier with my choice.

With the new motor I also installed a SmartCraft System Monitor thus I am now able to monitor my engine diagnostics and fuel consumption in real time. After installing the System Monitor it was eye opening to understand how much fuel is saved from simply not running at wot. Adding the use of GPS a guy can really understand/dial in his fuel mileage and speed when throttling back a bit.

With the 4-stroke I started saving some cash right out of the gates with not having to mix my gas. On top of this I now have a fuel injected motor which within itself is a gain. Beyond fuel mileage, It’s easier starting, easier to maintain and unbelievably quiet running. By adding the 20HP I gained about 9mph at wot though now I have the added power/mph’s to further throttle back after getting on plain…even with excessive throttle back I am still cruise 4mph faster than the older motor at wot.

Given these cumulative gains I am seeing slightly more than a 50% gain in fuel efficiency. 

Toby


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## Seth (Mar 26, 2009)

That's good to here Toby. How much heavier is the 4 stroke compared to the same sized Etec? Is it enough to bother worrying about it? The extra weight is the only draw back I've heard on 4 strokes.


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## Toby from MO (Mar 26, 2009)

Seth said:


> That's good to here Toby. How much heavier is the 4 stroke compared to the same sized Etec? Is it enough to bother worrying about it? The extra weight is the only draw back I've heard on 4 strokes.



My old 2-stroke was only 200lbs…talk about light weight.

My new Merc weighs in at approximately 270-280lbs. The same HP Etec weighs about 250lbs.

The way I rationalize weight (just the way I do it)…compare against similar items you readily carry in your boat.

Etec vs. Merc…30lbs. is roughly equal to a 3yr old child or roughly the weight of a trolling motor or roughly the weight of a medium sized cooler or roughly the same weight as a tackle bag…to me this was nothing. Never recognized a difference in speed with adding any of these items to my boat…even on GPS.

New Merc vs. old motor….80lbs is roughly the weight of 10gal gas or roughly the weight of small live well full of water or roughly the weight of large trolling battery. Sure this weight difference is a little more to consider but the added 20HP covers this easily…and then some.

I also wanted to know how much deeper the boat would float with all this added weight hanging off the back. Not only on plane, a guy needs to know what depth water he can float throw when fishing. So…I calculated the water displacement of my hull. Given a few known facts of my boat with the 200lb motor I was able to calculate the difference of adding the 80lbs to the rear…I lost about .33” of floating depth.

Regarding the 60/40 Etec…I will tell you this. My disclaimer…I have heard this from more than one reputable dealer. Don’t trust my word, ask for yourself. The 60/40 Etec has come with some issues…in jet applications. Specifically the rev-limiting chip. In random cases this chip had to be replaced for larger chips to allow the necessary RPM’s for this motor to function properly with a jet. Complaints of sluggish top end performance and excessive heat. If you are considering this it would definitely worth your effort to ask. Dealers, especially those who sell Evinrude, may not openly admit to this. I was danged near on a first name basis with a few dealers before I got them to admit this was an intermittent issue. At this time Evirude may have resolved the issue but you never know. Regarding all the other Etec sizes…these same dealers claim to have had zero issues. 

Toby


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## bassboy1 (Mar 26, 2009)

The new DI technology is almost as heavy as the equivalent 4 stroke, so that is now a moot point in the 2 stroke vs. 4 stroke debate.


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## Seth (Mar 26, 2009)

I don't plan on buying anything for a while. When I do though I'm not getting anything less than a 90/65. I'm not an Etec, I was just curious since you mentioned Yamaha and the Evinrude.

You really know your stuff when it comes to these jet rigs. =D>


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## Toby from MO (Mar 26, 2009)

Seth said:


> I don't plan on buying anything for a while. When I do though I'm not getting anything less than a 90/65. I'm not an Etec, I was just curious since you mentioned Yamaha and the Evinrude.
> 
> You really know your stuff when it comes to these jet rigs. =D>



If you are referring to me…not really. I only know what I read, been taught or learned through experience. All the guys I hang with on the river are also jet boaters. We all have our personal preferences so I get alot of comparison information from them. Not to mention I am an engineer by trade…meaning I’m obsessively anal about small details.

I have no experience with Yamaha's. The only information I have gathered about these engines are that they are well designed & reliable. I have ridden in a few boats powered by the older 2-stroke versions...they run good. I've had one passer by on the river claim his new 4-stroke was slugish on the bottom end...one other dealer said the same.

The 90/65 is a great middle of the road choice. BTW...what rivers do you run on?


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## Kawriverrat (Feb 2, 2010)

I'm Jeff, it is great to have found this sight. Some of you aren't far from me. 
Some info here some might find helpful. 

These stats are with jet. Just remember the rpm & gallon per hour stat will be the same for any boat. A jet doesn't care what its pushing it will burn the same amount of fuel at a given RPM regardless of size or weight of boat it is put on.

It just takes more RPM to push bigger & heavier. 

Bigger motor will do it at less RPM. So if the outboard your using is running at the upper edge of its RPM range to stay on plane, a bigger outboard could give you better fuel economy. 

E-Tech 115 hp 
1760 / 900 lb. boat

3500 rpm /12.1 mph/3.72 gph 

4000 rpm /22.5 mph/4.50 gph

4500 rpm /27.7 mph/5.98 gph

5000 rpm /32.1 mph/6.93 gph

5600 rpm /37.1 mph/11.02 gph


E-TECH 150
2076 / 1500 lb. Boat

3500 rpm /23 mph/6.0 gph

4000 rpm /28 mph/8.0 gph

4500 rpm /32.4 mph/10.5 gph

5000 rpm /36.6 mph/13.7 gph

5100 rpm /38 mph/14.0 gph 


E-Tech 200 hp
Same boat as above

3500 rpm /22 mph/8.5 gph

4000 rpm /28 mph/10.7 gph

4500 rpm /33 mph/14.50 gph

5000 rpm /37 mph/17.75 gph

5100 rpm /39 mph/ :shock: 20.0 gph :shock:


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## Seth (Feb 9, 2010)

Thanks for stats. Man there's a heck of a jump going from a 150-200!

BTW....Toby I run on the Gasconade and Osage River's most of the time. I know you asked me that almost a year ago , but I just now seen it.  

Also, I went to Cowtown USA and priced a 2010 1852 Legend SS with a 115 Etec and they said 24K! That just sounds ridiculous. I've seen a couple of 1860 Legend's with 225 etec that were 2006 and 2007 models for $20k on Craigslist. They also had a dual console red 1960 with a 250 HO etec on the back for a measly 37k. Is that comparable to other places or are they just way more expensive?


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## Codeman (Feb 11, 2010)

Did you try Ernie's sales and service aka Jet Doctor? 

https://jetdoctor.net/index.php (Ellington, Mo.)

Also Trout and Son's (St. James, Mo.)

https://www.trouttandsons.com/index.html

Current River Marine. (Doniphan, Mo.)

https://www.currentrivermarine.com/


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## Seth (Feb 12, 2010)

I'm gonna talk with troutt and sons and eberlin boats this weekend at the boat show in STL. Troutt is only a 30 minute drive from me and eberlins is about 45 minutes. I wonder if the Ernie guy will be at the boat show or not. Does anybody know?


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## Codeman (Feb 12, 2010)

I'm guessing no but who knows. I'd just call them.


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## S&amp;MFISH (Feb 13, 2010)

Hey Seth, when you go to the Troutt&Sons booth don't be afraid to talk to Kim.She knows her stuff. She is who sold my boat to me,she bent over backwards to get me in mine.


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## Kawriverrat (Feb 16, 2010)

Seth said:


> I'm gonna talk with troutt and sons and eberlin boats this weekend at the boat show in STL. Troutt is only a 30 minute drive from me and eberlins is about 45 minutes. I wonder if the Ernie guy will be at the boat show or not. Does anybody know?


 Eberlins seems to have the best no haggle pricing. They are who I will probably buy my next boat from.

For what its worth I am staying with a boat that can be efficiently powered with a 90-115 hpb outboard.
That in my mind is the best power for fuel used available. While also being able to push a respectable size boat with a jet.
Fuel cost will never do anything but go up. Wouldnt take to much for us to see $5.00 or more a gallon for gas. Last thing I want right now is a boat payment along with high priced gas.


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## Codeman (Feb 18, 2010)

Kawriverrat said:


> Wouldn't take to much for us to see $5.00 or more a gallon for gas. Last thing I want right now is a boat payment along with high priced gas.



Bite your friggin' tongue.


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## Kawriverrat (Feb 18, 2010)

Codeman said:


> Kawriverrat said:
> 
> 
> > Wouldn't take to much for us to see $5.00 or more a gallon for gas. Last thing I want right now is a boat payment along with high priced gas.
> ...


I know....... I hate thinking about it. Had to quit watching the news for a while it was just bumming me out.


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