2 vs 4 stroke, same RPM, same HP, 7lb weight difference?

[KC8QVO]

From past research and discussion it appears the general consensus is a 2 stroke is a stronger running motor than a 4 stroke. I was looking at specs between the 50hp Merc 4 stroke and Evinrude 50hp ETec. The ETec is 240lbs and the Merc is 247lbs. Both motors are spec'd at 5500-6000rpm. Does, what I'll call, "conventional wisdom" hold true in that a 2 stroke is still a stronger motor?

Or are the differences between a 2 stroke and 4 stroke more in the mechanics and maintenance of the motors - as in no oil changes for a 2 stroke, etc? I didn't happen to spot if the Etec's in the lower hp ranges are oil injected or not, but if not that would be another consideration - mixing fuel vs. straight gas in the tank (goes in my term of "mechanics" above).

 

[Georgesalmon]

horsepower is horsepower. You will need to put twc-3 oil in any 2 stroke all the time. No mixing oil in the tank anymore, they are all oil injected. used to be 2 strokes had a little more torque at lower speeds but not much anymore. EPA keeps adding regulations about air pollution so 2strokes are on their way out, though with new advances the E-tech is meeting the latest regs. JMHO, I'd go 4 stroke.

 

[roscoe]

Etec for easy of use, service, and boater envy.

 

[steelespike]

Lake Tahoe banned motors that don't meet CARB regulations.
They have selected the Evinrude Etec motor as their official motor.
The Etec is a direct injection motor. Referring to injecting fuel into the combustion chamber similar to automotive fuel injection.
Lube is also controlled.
A 2 stroke piston fires every time it reaches top dead center.A 4 stroke makes 4 strokes to fire once.
Horsepower is horsepower but it is a different power curve.
A 2 cylinder 2 stroke has about 7 moving parts if you include the flywheel and reed valve assembly.
A 2 cylinder 4 stroke has about 19 moving parts.Thats a lot of reciprocating weight.

 

[dingbat]

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[nwcove]

If you like dumping $40 a gallon DFI oil in the fuel tank on an ongoing basis, go with the Etec. If you like to gas and go, get the 4 stroke.

could be very wrong as i have never owned or plan to own a 4 stroke ob, but i would guess ....and only guess, that over the expected life of both types of engines, the 2 stroke would end up the winner as far as $$$ spent goes. jmo

 

[dingbat]

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[Chad Flaugher]

Lets turn the tables for a hot second... Back in the day, I used to race motocross. You'd get laughed off the track if you showed up with a 4 stroke. Now it's the complete opposite! Now lets look at lawn maintenance equipment... Whats new with blowers and trimmers? Yup, 4 strokes are sweeping the market. With new advances in internal lubrication and copyright releases, 4 strokes are becoming more versatile, lighter, stronger, and efficient than ever before. There is certainly nothing wrong with the 2 strokes, but a brief 30 year timeline kinda tells you where 2 strokes are heading...

 

[Sea Rider]

I'm a 2 strokes junkie, if in a future 2 strokes will be banned will move directly to 2 stroke Evi Etec, Tohatsu TDLI type engines, 4 strokes requires much more time service compared to.

Happy Boating

 

[KC8QVO]

I guess I am going to have to as a dumb question here. The last big 2 stroke we had was a 175 Etec (early 2000's I think) and I never put oil in it (boats are stored and maintained by the local marinas - never ran through a tank of oil while I was there). All the portable outboards we have are older Johnson 2 strokes (all carbed) with mixed fuel. So where are the oil tanks for the motors that have the oil injection?

Something tells me ours was under one of the back seats adjacent to the battery, as opposed to under the cowl, but I'm not positive and we don't have the boat anymore. I suppose the answer to that question may be with the hp range and/or series of motor? Or are they all remote tanks?

Another, somewhat offtopic question, but with all the gizmos and electronics on these newer small/medium hp motors - how hard is it to connect to NMEA2000? Are there controllers to Y in to or is it more of a hard-wired tap of the system and sensors?

 

[gm280]

As usual this question is like asking Chevy or Ford, or best lower foot oil, best 2 cycle oil, best boat wax, or even best wheel bearing grease! Everybody like theirs the best, of course, or they wouldn't be using it. But understand some things between the two systems. 2 cycle engines use mixed oil/gas because that IS the only way to lube the internal bearings and such. 4 cycle engines have way more moving internal parts and therefore more internal friction to over come. It HAS to have a crankcase filled with oil to lube its internal parts. 2 Cycle engine fires at every TDC (or there about) while 4 cycle uses two TDC (or there about) strokes to fire. Obviously there are different power curves between the two designs. As far as pollution factors, it would seem that 2 cycle have more output pollution then the 4 cycle. But both output their exhaust into the water and the EPA would love to shut down both systems if they thought they could get away with it without lose of life. I see some even remark about small lawn and yard equipment going to 4 cycle as well. I have some of both types and can tell you they are not there yet. Both have problems, while different, they're still problems. I'm sure one day I will be forced into 4 cycle OBs and will live with it and learn about their care as well. But I have to admit, 2 cycle fumes early in the morning is pretty good smell to me...yet! On a slightly different issue but still somewhat the same, the EPA makes us pay now to have our old tires disposed of via extra money. But think about this for a second. With literally hundreds of million of vehicles driving the roads everyday, and knowing we all are wearing down our tires, where does the EPA think all that tire wear is going to? It doesn't magically disappear into the never never land. It is being deposed along every roadway daily in the tons of rubber particles. So why charge everybody extra for disposing their old tires? The 2 cycles rein IS coming to their end, but probably not in my life time...

 

[dingbat]

But I have to admit, 2 cycle fumes early in the morning is pretty good smell to me...yet!

I got a chuckle out of this..... two stroke fumes are probably the number two cause of getting green, right behind that greasy sandwich they had for breakfast...lol

 

[dingbat]

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[minuteman62-64]

On a slightly different issue but still somewhat the same, the EPA makes us pay now to have our old tires disposed of via extra money. But think about this for a second. With literally hundreds of million of vehicles driving the roads everyday, and knowing we all are wearing down our tires, where does the EPA think all that tire wear is going to? It doesn't magically disappear into the never never land. It is being deposed along every roadway daily in the tons of rubber particles. So why charge everybody extra for disposing their old tires? The 2 cycles rein IS coming to their end, but probably not in my life time...

The used tire issue is a little more complicated. Most landfills will not accept tires for disposal because they don't compact - in fact, they literally "walk" up through the compacted trash and end up on the surface. So, before the disposal regs/fees a lot of used tires ended up dumped by roadsides or piled in canyons (big fire hazard). The fee pays for (in theory) the proper disposal of the old tire - which is recycling. Less of an issue here in San Diego where a lot of used tires seem to end up as retaining walls in Tijuana

 

[minuteman62-64]

And, excuse me for carelessly contributing to thread drift.

 

[WIMUSKY]

Yeah, let's get back to talking about OBs........

 

[steelespike]

If you like dumping $40 a gallon DFI oil in the fuel tank on an ongoing basis, go with the Etec. If you like to gas and go, get the 4 stroke.

If we're going to compare DFI oil the Oil changes should be compared using high grade Synthetic oils.
You can run any good TCW3 rated oil.The motor can be programmed.
No service required for 3 years or 300 hours.No breaking period.
If I could afford it I would go to the 60 Etec the the 50 and 60 are the 40 higher tuned. The 60 is slightly more efficient. at the same weight. 240.

 

[nwcove]

could be very wrong as i have never owned or plan to own a 4 stroke ob, but i would guess ....and only guess, that over the expected life of both types of engines, the 2 stroke would end up the winner as far as $$$ spent goes. jmo

I go thru 1,000 to 1,200 gallons of fuel a year. At 75:1, that's 16 gallons of $40 a gallon ($640) 2 stroke oil compared to one, $25 gallon of 4 stroke oil per season. A no-brainer....lol

i was thinking about more than just oil.

 

[pecheux]

I love 2 stokes OB's and the smell of the 2 cycle oil fume. That being said, IMHO a 2 strokes sounds more 'natural' at WOT, as 4 strokes seem to labor. :grumpy:

 

[dingbat]

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