2 stroke vs 4 stroke - why the 4 stroke?

[mjw930]

All the talk about the ETEC is interesting but unless someone has information to the contrary, the Opti isn’t nearly as clean which makes the discussion irrelevant.

[Markus]

All the talk about the ETEC is interesting but unless someone has information to the contrary, the Opti isn’t nearly as clean which makes the discussion irrelevant.

Isn't it? What kind of emissions are worse? Hydrocarbons? Total emissions is a meaningless number, adding apples, pears and bananas together.

I thought Optimax outperformed eTec on pretty much every dimension, except love by people who used to make their living fixing broke OMCs. Why else would BRP compare it against over-propped 4-strokes and not the Opti?

[PanRonnie]

Just wait till they put catalytic convertors on them..

they have!

[Bruce2]

Yes i know Mercury has been working on a catalytic convertor.

[mercrazy]

the oil is what i smell.

[billybob]

I have rigged, run, & repaired, 100,s of tournament bass boats with merc. & yamaha 2 & 4 strokes. I have not yet found, a 4 stroke that will out accelerate a 2 stroke of the same horsepower. Will 4 strokes live longer than 2,s, hopefully. My only other opinion is the fuel saving. 4,s get much better mileage, but you better run them alot to make up for cost diff..

[Dave S]

Just give me a 120 Force.......

[Fishinmymission]

I have rigged, run, & repaired, 100,s of tournament bass boats with merc. & yamaha 2 & 4 strokes. I have not yet found, a 4 stroke that will out accelerate a 2 stroke of the same horsepower. Will 4 strokes live longer than 2,s, hopefully. My only other opinion is the fuel saving. 4,s get much better mileage, but you better run them alot to make up for cost diff..

Mercury actually sponsored a side by side video putting the 115 four stroke against the 125 optimax. The 115 four stroke was all around better which is why mercury no longer offers a 135 or lower optimax.
Possibly there has to be some base size to the motor before the weight and drag coming from all the DFI equipment actually starts to provide benefits over the newest four strokes. I feel like four strokes have reached their peek though and will not ever surpass any of the larger two stroke DFIs.

Now on the larger motors 150 plus no one seems to touch mercury DFIs for efficiency and power vs weight. I own my 175 optimax love it and scratch my head why I don't see a single other optimax on salt water in CT. Everyone else at my harbor has an old two stroke, a verado, yamaha which seems to be most popular, or there is even one or two ETECS. The DFI two strokes have a little more maintenance and things you have to keep your eyes on, Compressor(piston, lube, bearings reeds, belt), fuel injectors, Fuel rails and few valves, intake reeds. The pin point electric oil injectors seem to be doing a great job and I haven't read about any failures. I think people just got scared of all the early optis and ficht motors and people never wanted to really trust DFI two stroke again especially for offshore fishing. I personally have one friend with horror story after horror story about his 2001 3.0 liter optimax.

4 strokes really are a great keep it simple technology that has been around and optimized to be reliable for so long. They have great control over receiving clean air each cycle. 4 strokes have a mechanical oil pump that is reliable time tested and does a great job of lubricating all the needed components. They utilize the fuel to keep all the valves in the engine clean. And dual injection four strokes that use both DFI for efficiency and port fuel injectors to clean the valves seems to be the latest craze in the car industry for efficiency. We'll see in 10 years how these overly complex engines stand up to the test of time.

[Forkin' Crazy]

run a g2 inside a closed shop a few minutes and tell me they don't stink and pollute.
the epa test just doesn't measure synthetics.

Who the hell does that? Even with a 4 stroke motor??? "The EPA doesn't measure synthetics"? You have a citation for that? Oh and what about the waste oil 4 strokes create?

[Forkin' Crazy]

Just give me a 120 Force.......

235 Crossflow!

[powerabout]

Johns Custom Marine had etecs engines in test tanks in their showroom.
When you walk past a 4 stroke they are so rich to meet the emission regs they stink, try that in a showroom and you would die.
EPA not measuring CO yet

[FMP]

Just give me a 120 Force.......

or a 150?

[Dave S]

I used to buy Motors from a yami dealer. He thought I was a Jerk....250$$ for a 120 Force. A crabber had a 140 suzickey that had broken the top crank. Put the force on and he was happy.... used less gas and better running. He was happy. I made $$$$. A local buyer from Nigeria cam and bought all the yammi 2 strokes around. The poor people know how to fix non teck motors with wrenches . This new stuff is fine If your rich... and willing to lose $$$ .

[David]

I still wonder how the 4 strokes took over. More complex, heavier, and less torque.

Sure pre DFI 2 strokes were thirsty and smokey. Anyone want to see my 225 Promax? But the DFI engines are clean and quiet.

merc and Yamaha are increasing displacement to make torque, and it seems Merc is working on weight. Where would 2 strokes be with the same development $ put into them.

i don't know if I should buy a DFI motor while I can or enjoy my Promax. The Promax to me is the high water mark of pre emission outboards.

[powerabout]

I think it was a bit of quality control when others lacked...
For sure if the lightweight casting techniques are used on the 2 strokes, they will be lighter.
Wait till 4 strokes get cat cons and then see who is lighter