2 stroke vs 4 stroke

[naturewaterboy]

Where can one find objective info on comparing the direct injection two strokes to 4 stroke outboards? There are lots of opinions out there, but has anyone done really objective data collection on this subject? What are actual maintenance and operating cost of the engines? :confused:

[FAST FRED]

Can't give you any numbers , but how many hours do you think it will take to service 4 valves per cylinder on 6 cylinders?

Dealers are $75 an hour, and these are a bit complex for a backyard "mechanic".

FAST FRED

[Frosty]

Yeah ,--- I would stick with a 2 stroke for the time being.

[naturewaterboy]

I talked to a local mechanic today - he said that the new HPDI two strokes do not hold up - his explaination was that they run so lean that they burn up. He recommends to stick with the EFI two strokes - good on gas milage and long lasting. Anyone have any comments on the HPDI vs EFI? How does the fuel consumption compare on these?

[Loveofsea]

earlier this year i unbolted a yam F-100 4 stroke and replaced it with a merc 115 Opti. All other things being equal, i am now running a full 5-6 kts faster and i am getting .2nmpg better range. I am never going back to a 4 stroke.

For the same weight, why not opt for the extra HP?

[glen1941]

Hello,
This is my first post, and am not really sure what happens next. My situation is that I just bought a 1995 Montauk with 1995 direct oil injection 90 hp Yamaha 2 stroke. Boat was in Michigan and Florida with very little use when I bought it. Brought the boat to Birmingham and had local marine service go through from bow to stern. Alabama Marine pronounced the engine as being in great shape. My experience is with larger boats: diesel and I/O and am unfamiliar with outboards. The 2 stroke reminds me of a lawnmower [which I could never get to run], I listen to the "pop pop pop" and expect the thing to quit. I know that all this is me not understanding the engine. Where do I start to learn about these Yamaha outboards in order to enjoy it and keep it running? Am reading / listening about stuff like fuel additives for non-guming, "ring-free", etc. What are the traditional things that go wrong with these engines? Any help is greatly appreciated.

[RAWRF]

If you are running a 2 stroke I would mix the gas (and keep oil in the pump as well) regardless of what the manufacturer says. Those oil injected 2 strokes are injecting oil at the rate of 100 to 1, possibly more. You can mix up gas at 40 or 50 to 1 and still never foul a plug even if you are going slow all the time, which most people don't do. I have nothing but good things to say about Yamaha engines, I have a 1985 25 horse 2S that is still running great, as well as a 99 2S and an 03 4 stroke. Those new 4 strokes are great on gas, I wouldn't believe everything you hear. Loveofsea is the only person I have ever heard of who would choose a Mercury over a Yamaha, I have had nothing but bad from Merc. For people who want to stick to American made, Johnson all the way, they last forever.

[Loveofsea]

Hello RAWRF~

i have less that 90 hours on this engine and i am running between 44:1 to 51:1 fuel/oil ratio. The varience is a function of the computer according to its demand parameters. The specs are a bit ambiguous. Reliablity is my biggest concern and i don't mind the expense of the oil consumption if it is going to protect that powerhead.

The Yam F-100 has a tiny lower unit and couldn't withstand the rigors of a SST prop. i was at an island 75nm from port when it gave out without warning @ 700 hours. (when i think about all the places that thing could have failed, i am humbled by the coinsidence of good fortune~:)

anyway, i sold the motor with a new L/U (150hrs) to a friend for a song.

So far i am very pleased with the Opti. For years i have cruised at 22-24kts, now when the seas are kindly, i run 28-30kts with better fuel economy than the yam @ 24kts.

For me, it is all about range; range broadens your options like nothing else...

[RAWRF]

Getting back to the original subject, objective data of 2S vs 4S, the only data I have ever seen is from Bombardier, so I don't know how objective it is since they own OMC. I personally wouldn't own an Evinrude E-Tec HPDI 2 stroke, too much to go wrong with all the electronics controlling everything, and I live nowhere near a dealer with a certified mechanic, tho I am sure the others with EFI are just as prone to problems in that regard.
Hello Loveofsea--what exactly did you change from stock when going to the SST prop? i.e. pitch and size? I know they are stainless so they are heavier, is that why the Yamaha LU went out? I don't want to make the same mistake, although I never run stainless anyway, would size tend to do that also? Is the small lower unit inherent in all Yamahas? I have never had a problem with mine and never gave a thought to the lower unit. Thanks

[Loveofsea]

Hello rawrf

I never used an aluminum prop so i don't know how it would compare to the SST. I was told by the daler that sold me the lower unit that they don't handle the extra weight of the SST prop. He was a yam dealer and he said that every time you engage that heavy prop, it wears out the dogs just a little. The size of the prop probably won't hurt your L/U as much as the powerhead if it were grosely oversized. If you are running an aluminum prop i wouldn't worry about it.

i looked at the E-tecs and after having a problem with the voracity of the people at evinrude, i got my deposite back and went with the Merc. So far i am very pleased with that decision.

[RAWRF]

I use aluminum because I run exclusively on a river and hit bottom pretty regularly, and with a stainless prop you will wear out your lower unit with repeated small hits or, with a bad collision, break the clutch dogs, bend the prop shaft, and other things. Plus aluminum is cheaper.

[Loveofsea]

RAWRF, you say:

Loveofsea is the only person I have ever heard of who would choose a Mercury over a Yamaha.

That may be true from your experience, but you also don't know anyone else who runs these seas like i do :)

If there is something you can tell me about Mercury or Yamaha that i am not aware of, i'd be all ears...

:-)

BTW, i've had two Yamahas and i dumped each one for a merc....the yams were the only two engines that ever failed me...never again...

[cookiesa]

Evinrude ETEC over 4 stroke for me.

It isn't mine but we looked at both and have a mate with an almost identical boat (5m) with a 4 stroke. We get very similar fuel economy but plane much faster. The 4 stroke I reckon is slightly quieter. (Different brands so that could also be the difference)

[redtech]

boy you opened a can of worms
this is the classic ford vs chevy argument everyone will say something in the end its up to you
have them both two stroke with 3000hr and four strokes with 3000hrs bottom line they both do the job and if you take care of them they take care of you
not going to say any names so find out what dealers are in your area and what there techs say if you find an honest tech he'll tell you there all good but this is what he works on

[saltflower]

i work on harbor patrol boats using 150hp hondas,we switched from cummins diesels with outdrives and have found them to be nearly as fuel efficient as the diesels and much smoother and quieter.honda rates them as 10,000 hr motors and the coast guard locally rates them at 15,000. we've been extremely happy and put a minimum of 2500 hrs per season on them.

[marshmat]

We might be approaching a point with outboard engines where, as has been the case for a while with big diesels (DD vs Cat, etc), the argument of "2 vs 4" is becoming secondary to other considerations. The modern direct-injected 2-stroke and the modern 4-stroke are now roughly comparable in power, reliability, fuel consumption, cost and weight. The differences between the two types, based on these factors (which are really all the average boater cares about, in the end) are at present miniscule (on the order of 10%), and the categories overlap more than they are distinct.
My advice is, you can't base your decision solely on number of piston strokes anymore. Look at how the engine's power curves compare to what you want to do with it, look at where the dealers are and how honest/sleazy their mechanics, look at the tradeoffs between price and power, or between reliability and weight. List the criteria you need your engine to fulfill, figure out how you'll weight them, and buy the engine that fits them best.

[RMSOSF]

Where can one find objective info on comparing the direct injection two strokes to 4 stroke outboards? There are lots of opinions out there, but has anyone done really objective data collection on this subject? What are actual maintenance and operating cost of the engines? :confused:


I am a marine mechanic here in Fla. Typically, a four stroke outboard will cost you more in maintenace than a two stroke couter part, but not much more. with a four stroke, you have these items to do once a year (or every 100 hours):
1) Oil change . 3 - 5 qts oil and filter.
2) Gear oil change 2 - 3 qts of gear oil.
3) Thermostat replacement.
4) Water pump impeller replacement.
5) Spark plug replacement / compression test.
6) Fuel and air filter replacement.
7) Check / adjust all linkages.
8) Grease all fitting.
9) R&R prop, grease splines.
10) Decarbon.
11) Sea trial.

Two stroke:

1) Replace head gaskets.
2) Gear oil change 2 - 3 qts of gear oil.
3) Thermostat replacement.
4) Water pump impeller replacement.
5) Spark plug replacement / compression test.
6) Fuel and air filter replacement.
7) Check / adjust all linkages.
8) Grease all fitting.
9) R&R prop, grease splines.
10) Decarbon.
11) Sea trial.

Engine manufacturers have their own guidelines, but from experience, the list above is highly recommended.


As far as operating cost, the two strokes will burn far more fuel and you have to buy oil at a gallon for every 75 - 100 gallons of fuel.

Over all, four strokes will cost you less, but they are heavier and slower than a two stroke..... the choice is yours.

[Frosty]

On the 4stroke list you made no mention of valve adjustment or checking clearances. There has to be a check somewhere on its life, unless they are hydraulic?

On the 2 stroke list I disagree with changing head gaskets ever 100 hours. Unless you mean re torque after first 100 hours.

Changing a thermostat every 100hours?
Changing impeller every 100hours?

I dont think youve cleared the confusion between the 2 but certainly helped to clear the confusion of why does proffesional maintenance cost so much.

I think 100 hours on the gear oil is exessive too. AND spark plug replacement.

Errr --no mention of the cam belt then?

[RMSOSF]

Obviously, you don't think a rubber impeller should be changed at least every 100 hours or once a year (which ever comes first)?

Thermostats...... they clog up, if you pull them to inspect them, replace them.

Head gaskets on 2-strokes..... all the boats I work on down here are in salt water, a lot od corrosion. Also, there is a lot of movement due to the heads being so flimsy allowing the gasket to weep. Just look at any outboard used in salt water, if you see corrosion at the head/block joint, that is water weeping out......... and in. The only way to keep that in check is an annual inspection and replacement.

Gear oil..... why neglect the part that takes the most stress and beating.

To you it may be excessive, but to me, it's you being cheap on how you take care of your stuff. You will pay me now or later.......much more later.

Valve adjustment is not necessary on almost all 4 strokes... they are either hydraulic or shimmed on assembly or rebuild. the only time the adjustment goes out is if you warp a head or wipe out a cam.

As far as the cam belt... check and adjust evry 100 hours, replace every 200 hours. ....you lose a belt, you trash your heads. Most outboards only live to about 1500 - 2000 hours..... only the ones that are pudently taken care of make it to 3000 hours and more.


P.S..... The cost of prfessional mechanics are so high due to the training we must go through to work on these hi-tech machines, not to mention all the EPA, DERM, Dispoasal, Permit, License and insurance costs and the cost of living. The average marine mechanic only makes $30,000........... not even enough to buy a house down here. Oh yeah....... we also have to buy our tools...... I have $350,000 in tools right now, so don't get me started on how much we charge.

[Frosty]

Yes I do think that changing the water pump impeller ever 4 days of constant use is exessive.

Dont you fresh water flush?

You didnt mention anodes?

Dont 4 strokes suffer from head gasket/water absorbtion too.

You never ever check valve adjustment? even on shimmed vales?

Change Cam belt 200hours?? Do you ever get to use the engine? What egines are these?

I removed an impellor from one of my engines last month --they are original supplied with the motor 4 years ago. It was as new.

[RMSOSF]

forget it

[Frosty]

Sorry RMSOSF I was looking forward to a good debate on 4 stroke motors, Oh well!!

[redtech]

maintenance on two and four stroke engines do very some i do agree i've only ben wrenching 16year now on outboards and if you differant techs they will all say something differant
i myself don't agree with rmsosf's list 100% but can't knock it if asked personally about maintenance i do give customers copies of the maintenance schedule right out of the service guides this does end a lot of agruments about the work to be done
as far as water pump impellers this is the second most neglected and miss understood part of a boat (four years will not look new if you know what to look for)
trying hard not to say to much but everyone has one and nobody listens to another!!!!

[Frosty]

Pehaps I should have said --sevicable--Full water pressure no overheat at all.

I do not think that as I have spares on board anyway that I should replace an impellor because a book says so.

A technician should be able to tell if it is servicable -- ie all blades intact with no cracking around the base of each blade. Blades not distorted beyond servicability.

In the old days workshop mauals did not say replace,- it said remove and check for sericability.

[Loveofsea]

The old outboard engines used to have impellors that were not centered in the housing so one blade was always left bent against the housing when the engine was not running. All newer outboards have centered impellors so unless they have overheated due to starvation, they should easily last 600 hours +. Now days, the most important reason to change the impellor at less than 600 hours is to be able to separate the lower unit before it freezes up.

I recomment you install a water pressure gage, it takes all the guesswork out of your impellor performance~

[RMSOSF]

Pehaps I should have said --sevicable--Full water pressure no overheat at all.

I do not think that as I have spares on board anyway that I should replace an impellor because a book says so.

A technician should be able to tell if it is servicable -- ie all blades intact with no cracking around the base of each blade. Blades not distorted beyond servicability.

In the old days workshop mauals did not say replace,- it said remove and check for sericability.



Yeah, try replacing that outboard impeller 10 miles out to sea in 800 feet of water :rolleyes:

[alan white]

How does the ETEC engine work? Does it need oil injection? Or is it gas only, with a pump to inject the fuel instead of the crankcase-as-pump?

Alan

[Frosty]

Yeah, try replacing that outboard impeller 10 miles out to sea in 800 feet of water :rolleyes:

Fair point and one that I was going to mention . Engines do have different roles and if it just pushes a dinghy to shore and back then you can row home but I still maintain 100hours ie exessive.

[redtech]

How does the ETEC engine work? Does it need oil injection? Or is it gas only, with a pump to inject the fuel instead of the crankcase-as-pump?

Alan
:) :) the e-tec works by injecting the oil it needs to the crankcase so yes oil does enter the crankcase and then to the combustion chamber kind of like two stroke motorcycles have bin for years
as for fuel it has an electric fuel pump that feeds the injectors then the injectors are not a conventional injector but (bottle cap injectors) they are a high-pressure pump as well controlling the pintal three ways and these injectors are mounted in yhe cylinder not the intake

[alan white]

Thanks! And going on-----------How does this engine do in terms of emissions? I know that common two-stroke engines fail miserably to meet even the most lax standards. If the oil is being burned, is it done in such a way as to limit emissions to levels competitive with four stroke outboards?
Because I would see emissions as a factor in choosing this engine, along with all the other variables. In fact, if it produced (in circumstance in which I would use the engine, i.e., all things considered) pollutants above the average four stroke, that alone would outweigh any other factors.

Alan

[cookiesa]

The ETEC emissions are below the EU requirement for 4 stroke engines. They are also almost as quiet (You can easily talk to each other in a 5m runabout at 3500 rpm) as a 4 stroke.

[redtech]

the emissions are below c.a.r.b. and epa so even in california there no problem and the tree huggers in tahoe even use them on there patrol boat
c.a.r.b. post there emissions on the web california air resource board
i believe so do the e.p.a. on a total the e-tec is below the four stroke on emission when measuring both hyro-carbon and NOx (sorry spelling isn't my strong point) the hydro-carbons are unburned fuel and NOx is the harmfull gasses the US measures mostly hydro-carbon but is starting to measure NOx EU standards are NOx but not hydro-carbons
how clean? the e-tec can be used in bodensa in europe this lake has the tightest regs of any place in the world a lot of 4-strokes don't make there

[alan white]

Thanks to all who responded. Interesting and if fuel economy is good, then all the better. Wonder where we'll see this engine appear next? Motorcycles?

A.

[redtech]

Thanks to all who responded. Interesting and if fuel economy is good, then all the better. appear next? Motorcycles?
Wonder where we'll see this engine
A.
don't know where it may show up. by ways of tuley telegraph was said GM was looking into this motor for a while:?:

[naturewaterboy]

The Evinrude E-tec has a c.a.r.b. 3 star rating - does any other engine out there have three stars? It seems to me that all of the four strokes I've seen and the other HPDI 2 strokes only have a two star rating.

[redtech]

yes there are other engines two and four stroke running 3 star but if looking for emissions only see about those running 3-star carb. epa rating and have eu rating this will be a smaller list

[Loveofsea]

Mercury Optimax is a 3 star engine. I chose the Merc over the etec because the people at evenrude customer service lied to me about their product. I lost faith in the company and got back my deposit and went with the Opti. I am very glad i made that decision. Merc's 3 cyl 115HP is the largest displacement 3 cyl on the market. There is no way the 4 cyl Etec 115 can be as fuel efficient as the 3 cyl Opti.

[redtech]

i'm sorry to that someone has lied to you or that you do feel that way Loveofsea
as far as fuel efficient jaguar did prove more cylinders can be better with a 12 cylinder 350cid engine vrs an 8 cylinder 350cid engine and while at cruising speeds you can get better fuel milage with twins over a single when at staying out of that extra power
it take s a lot of set up and knowledge to get the best fuel efficiency possible on any boat so I hope you were able to get a knowledgable technician to help you achieve this my experance is merc mechanics do mercs and john/rude mechanics do john/rudes most don't seem to do both, and neither do the sales-men

[alan white]

Seems it wouldn't matter so much how many cylinders an engine has in terms of fuel economy. It may have more to do with accellerating the rotating mass, which has to do with how an engine's used (generally, fewer cylinders have greater inertial mass for reasons of smoothing firing impulses. Constant accelleration/decelleration like a recreation boat encounters would favor a multi, while a water-taxi might favor a single. The single might edge out the multi in the right situation due to lower piston swept area per cu. in. ).
Of course, I'm just guessing. I'm no expert.

Alan

[Loveofsea]

The Optimax 115 (1526cc) replaced a Yam F-100 (1596cc). The smaller displacement 2 stroke Opti gets better fuel economy than the 4 stroke yam did. And it not only got better fuel economy, it cruises at 5-6kts faster. The etec 115 is 4 cyl and has a displacement of 1726cc. You never really know untill you test it, but i'm pretty sure the 3 cyl Opti would do better than the etec.

redtec, i put 3k down on a 90hp e-tec. The dealer told me the tillers were on back order and it would take 2 weeks to get it. After two weeks and the tiller was still a no-show, i called evinrude customer service and was told it would be another two weeks...this game went on for two months until someone from another message board sent me a link to the US Coast Guard recall website where it showed the all of the evinrude tiller handles were recalled two months before i put down the deposite! The dealer didn't tell me... evinrude customer service never told me that all of their tillers were recalled---they deliberately strung me out for over 2 months so i fired them!

i do underwater photography here in So Cal as a hobby and i boat year around. I do not enjoy being off the water for two months because those people saw fit to lie and game their own customer--

i built my own skiff and i have logged 55,000 miles of open seas in it. i have logged over 90,000 miles of open sea travel in the last 23 years. i don't think there is very much that an outboard tech is going to tell me about performance or set up...

[redtech]

loveofsea, i myself do remember the recall on the tiller handles and do remember the west coast was the last to get the new ones someone should have just told you about it in the first place.
did some research and the opti is more fuel efficeint than the e-tec by testing the trade off was emmisions but in california thats not as tight as most people are lead to believe
as for two stroke vrs four two stroke will always get better economy
i haven't done to many if any sea skiffs but in bass boats it's often the older boater that is stuck in there ways and not willing to try something new in set-up so don't take my suggestion the wrong way please
if we were not trying to learn something we woulsd not be here? sometimes even some of us old dogs learn from the pups

[olpsfam]

so the best fuel oil mixture for 1999 yamaha 90 is 100:1?

[StianM]

I remember when everyone claimed 2-stroke was out and from now on all outboards would be 4-strokes.

I called it ******** and 2 strokes have the advantake off less moving parts and less weight/hp and also less mecanical losses. They would be just as fuel efficiant and have just as good invironment caracteristics once someone tryed to use the right injection tecnolegy. I ended up having right.

The moust fuel efficiant diesel is the sulzer and B&W two strokes, the moust fuel efficiant aircraft engine ever made is the Napier Nomad two stroke.
I feel the Two stroke trough all time has gotten a unfair reputation.

[alan white]

Anyone ever hear of a Wankel powered outboard? Very light, no oil mix, simple, and small for output.

[StianM]

Anyone ever hear of a Wankel powered outboard? Very light, no oil mix, simple, and small for output.

They made that???

I remember me and the first engineer on one off the boats I sailed talked about the posebilety of Wankel diesels for inboard use:p

[alan white]

No... I was asking! I have never seen one. Apparently, two strokes were more viable. So far as I know, the Wankel has never been a successful engine. I don't think Mazda uses them any more.
Funny, but the basic engines designed at the end of the nineteenth century haven't changed in any basic way. The Wankel was the exception, and it came close to being a fundamental change in engine design. And that was fifty to sixty years ago.

[StianM]

No... I was asking! I have never seen one. Apparently, two strokes were more viable. So far as I know, the Wankel has never been a successful engine.

http://www.mazda.com/mazdaspirit/

They still make them, but are only used in the RX-7 and RX-8 I think.
They use too mutch fuel to be used in annything else than a sports car.

[alan white]

Okay. Wasn't sure. Yeah, they use fuel--- and maybe they can't make them any more economical than piston engines.

[Frosty]

The wankel engine was used in the mazda, the RO80. Its only down fall was its smootheness and the idiots that drove them over reving ( the consiquences of its smoothness)

it has been used in a motorcycle too ( forget which one)

On the other hand the rotor tips have been improved now. I think the only reason its not seen more of is that people will just not move away from the piston engine.

I saw a wankel marine engine in a boat magazine some years ago.

[StianM]

I would defently buy a wankel if they could prove the same fuel efficensy as a piston engine and same service life

[alan white]

The wankel engine was used in the mazda, the RO80. Its only down fall was its smootheness and the idiots that drove them over reving ( the consiquences of its smoothness)

it has been used in a motorcycle too ( forget which one)

On the other hand the rotor tips have been improved now. I think the only reason its not seen more of is that people will just not move away from the piston engine.

I saw a wankel marine engine in a boat magazine some years ago.

In the sixties, the RO80 was an NSU, wasn't it?

[Frosty]

I think NSU had one as well --wasnt it called the NSU Quickly?

NSU did a 'Quickly' but it doesnt sound like a name you would pick for a Wankel motor.

But thers something familiar about your question.

[alan white]

NSU had the Prinz and the RO80, I think.
Johnson, in '73, had this:

http://sports.webshots.com/photo/2520111070091848696keHkxG

[Frosty]

Ok i cheated as well I googled ( shame)

Mazda and NSU did make the RO80

Never -ever seen the Johnson,-- wow- what happened to that.

Did it work?

[StianM]

Johnson, in '73, had this:

http://sports.webshots.com/photo/2520111070091848696keHkxG

A ugly looking thing. Was it a prototype or was it sold?

[razbarb]

I thought Mazda didn't use rotary engines more widely due to high fuel consumption and low torque.
Turbos changed the torque problem quite dramatically.
Look at the specs of the auto RX 8 compared to the manual, there's a big drop in hp and torque.
In my earlier days driving my RX 3, the guys in automatic cars never stood a chance on the street or track.
There is an engine builder in Melbourne, Aus that fitted a turbo triple rotor to a ski race boat.
There's a clip of it on you tube and the acceleration and sound are awesome if your'e a fan of rotary engines.
Website is http:/www.extremerotaries.com/ , click on the photos/videos link.

[alan white]

A friend of mine had a Mazda rotary mini-truck. This was a ways back.

[razbarb]

A friend of mine had a Mazda rotary mini-truck. This was a ways back.

I reckon your friend might of enjoyed driving that mini truck!
I remember seeing a racing beat mini truck with a turbo twin rotor (13B) in an Aussie car mag about 15 years ago.

[Raggi_Thor]

Citroen GS used a Wankel engine in the 1970s, for racing (?)

From http://members.tripod.com/mattysk/types/birotor.htm:


GS Birotor
In 1974 the without a doubt most remarkable GS was introduced, the 'GS Birotor'. After experimenting with the wankelengine in M35 (Ami coupé), Citroën introduced the Birotor as the next car with the so called wankel engine. The wankelengine was a product of the cooperation between Citroën and NSU. NSU produced the RO 80 with the wankelengine.
Unfortunately the Birotor was introduced at a bad time. The oil crisis asked for cars with low fuel consumption, the Birotor with it's thirsty wankelengine didn't became a succes. An other thing that happend was the difficult period Citroën was having in the mid seventies, just before the PSA takeover. Citroën decided to stop with the Birotor and recalled the cars to the factory. To prevent from having all the parts in stock. Luckely they didn't succed in recalling all Birotors. But of the 847 Birotors produced, only a handfull still exists. This makes the Birotor a very exclusive car, they cost small fortunes nowadays.

[ianper]

Is it true to say that new 2strokes are as thirsty as 4strokes at full speed? How do they compare at 3/4 full. Which would be the cheepest 2 stroke 150HP compared to a 4 stroke?.

[hmattos]

In our experience the Evinrude two strokes use the same fuel at full throttle as the fourstrokes - we use Suzuki - , but the lower down the speed range the better the Evinrude compares. Hence since most of our users spend 50% of their time at idle, they will use a little less fuel if they have an Evinrude.
As to servicing, the Evinrude wins every time