Give your opinions on attached 2 vs. 4 stroke article

[evin300]

Re: Give your opinions on attached 2 vs. 4 stroke article

Schematic, ODDD1, Djohns19, JS2, and gatr1, I totally agree with your opinions.<br /><br />I have been trying to convey Mr. Lamberts (professional) opinion all along. Many times I am only run over by the 4-stroke craze. I think part of the seduction of a 4-stroke is that people understand how they work, and they do "so well in my car".<br /><br />2-strokes however, seem to be misunderstood, many auto mechanics have come to this board for advice. Also, many people have the "old" two-stroke impression. Well, I say, wake up people! The real future in our boating lives is the "new" 2-stroke. However, I agree that 4-strokes will find limited use.<br /><br />Its time for some 4-stroke lovers to get a dose of reality in my opinion. As always, do the research, and be very leary of this 4-stroke fad. Just my .02

 

[Digdug]

Re: Give your opinions on attached 2 vs. 4 stroke article

Hey JS2, So that is why all the "crotch rockets" are 4 stroke! EMISSIONS!!!

 

[Franki]

Re: Give your opinions on attached 2 vs. 4 stroke article

Hey,, the gap is closing.. <br /><br />At the high end bike racing (not offroad), There are competitive 4 strokes now... and its only a very recent thing. There have been a couple of attempts to make competitive 4 stroke dirt bikes too, but they have yet to be very successful.. mostly because they don't have the sort of power characteristics that are required in motocross.<br /><br />Strangely enough, one of the companies that makes some of the worlds most advanced 2 strokes is actually Honda... the CR series. they don't have EFI because motocross hasn't alot of emmision regs, but honda I believe was the first to release AETC (Automatic Exhaust Timing Control) which sits in the exhaust port and changes the exhaust characteristics depending on rpm.. and thats been around in bikes since the mid 80's or before, but it hasn't found its way to outboards yet I don't believe...<br /><br />There will be more advances in both 2 and four stokes, and the result will probably be pretty much the same as they are now in relation to each other... in other words, both motors will get lighter, more powerful, faster reving, more reliable etc etc...<br /><br />In 2 strokes for example, if they figure out a way to seal the bigend and main bearings from the crankcase, and internally oil feed them.. then all they need to is possibly directly inject oil through the bottom or sides of the barrel (possibly through holes in the bore between the rings at BDC), and you have an almost "non loss" lubricating system... you would lose bore lube oil, but you lose some with 4 strokes as well... and the bore oil would be alot less then the amount of oil used in a two stroke now..<br /><br />On the other hand, four strokes can go a long way as well... <br /><br />So, essentially, nothings going to change, and no one is forcing you to choose one or the other.. so why argue over it? I'd love a modern variant of either...<br /><br />regards<br /><br />Frank

 

[rolmops]

Re: Give your opinions on attached 2 vs. 4 stroke article

JS2 <br />I do ride a bicycle to work...<br />Rolmops.

 

[davidd267]

Re: Give your opinions on attached 2 vs. 4 stroke article

Sorry Franki ESL 10072 but you are behind the times as Doug Henry won the united states National motocross championship in 1999 on a four stroke 426 cc motor cycle and just last week Nathen Ramsey won the dallas supercross on a 450cc honda four stroke bike . The AMA in its wisdom allows up to 450cc four strokes to compete with 250cc two strokes. The wieght differences are 250 pounds for a 426 yamaha, 234 pounds for a 450cc honda 212 pounds for a 250 honda two stroke. The four strokes have a small power advantage over the two strokes in exchange for a wieght disadvantage And almost double the displacement. How this transelates into marine engines to me is that in order to have comparable four strokes you must run them in a higher state of tune... higher compression ,greater valve overlap= less durability. Or perhaps we shouldnt try to make a four stroke be something it is not. If you want to run a four stroke motor on your boat dont expect it to have the same power to wieght ratio as a two stroke without paying in reliability or durability. I would rather have a four stroke moter in a low state of tune (lower power higher wieght)than one that is trying to mimic the power charecteristics of a two stroke. Hmmmm what about turbocharging to help ??????????

 

[G DANE]

Re: Give your opinions on attached 2 vs. 4 stroke article

Now i dont thing this is a matter of competing, as to chooose the type of motor that under normal conditions gives a good performance, compared to economy, weight, noise, adn cost. I still think the 2s does on outboards. By the way the 2S has had a comeback here in Europe. As you probably know cars and motorbikes are quite expensive due to VERY high taxes. What would people with lower income do for transport. 6 yrs ago a new kind of scooter was marketed, it is limited to 50 cc motor, weight below 90 kgs, speed in Denmark restricted to 30 miles, rest of Europe 40 miles. Taxfree. Every major motorcycle brand makes one now. Gues what type of motor ? a twostroke with computerized ignition timing, with rpm control, and oil injection. The motors are very advanced. A guy who removed the restrictors made one run beyond 85 miles at top !! The motors are great. Surely there are a huge potential in the twostroke - as the developing continues.<br /> http://www.suzukimotorcykler.dk/Scooter_45/Suzuki/ay50wrk1/ay50wrk1.jpg nice little thing !

 

[Capn Mike]

Re: Give your opinions on attached 2 vs. 4 stroke article

I despair about the future of 2-cycles when the authors of the first few posts responding above so obviously missed the point. And they're people who are boaters!<br />Down in Oregon...the leftest of the left coast... a nitwit legislator introduced a bill to ban all 2-cycle boat engines, while claiming that those engines "were the cause of 95% of all water pollution." The bill died a quiet death when cooler, and presumably more intelligent, heads learned about a thing called "newer technology." <br />In any case, I sure appreciate the maintenance needed on 2-cycle(change the gear oil and plugs once a year), and will run it to the death. We recently learned that the tugboats that run the Columbia River...and are so vital to our economy... cause more pollution than previously believed. It ain't easy to play God.

 

[Franki]

Re: Give your opinions on attached 2 vs. 4 stroke article

Blue water, I didn't know that, but it clears something up for me... (or maybe it proves my point.)<br /><br />If a four stroke has to be nearly twice the size as a two stroke, and worked to the eyeballs to compete with a two stroke.. what does that say??<br /><br />I think its alot closer in outboards though..<br />a CR250 for example, has a pretty advanced tuned expansion chamber exhaust on it, and it makes a massive difference to the power output.<br /><br />Unfortunatly, thats not easy on a 4 cyl outboard and as such they are much less effective.<br />They will probably do it though, four expansion chambers (or possibly one big one) leaving the four cylinders and exiting down the bottom..<br /><br />Will make the bottom of the leg much bigger then it is now.. but the power difference would be staggering.. and then you'd see the same sort of thing that the motocross engines show...<br />Its all good stuff, anything that advances both 2 and 4 strokes is good, as long as it doesn't preclude the other.<br /><br />Incidently, the last conversation of this nature on this list that I followed had a link to a marine company selling blown rotary marine engines.. If I remember correctly, it had 280HP and far less weight then an equiv inboard, and in fact it had less then most 4 cyl inboards and a good deal of outboards, (it was around 200kg or so i think, but I might be wrong about that..)<br /><br />One of the cat manufactures have just made it their standard powerplant... apparently it wasn't working to hard to achive that power either.. so reliability would be pretty good.. (the non blown version still had over 200HP, 230 I think.)<br /><br />Thats impressive technology, a rotary has some of the benefits of both conventional 2 and four stroke engines, and this one is based on a mazda 13B rotary.<br /><br />How long before one of those ends up on an outboard if they get popular as inboards??<br /><br />How long before a jap manufacturer decides to build a light weight version made from alloys as per current outboard materials?<br /><br />and with the japs developing them, they would probably overtake the 2's and 4 strokes pretty quickly.. <br /><br />Incidently, they also pass all the latest emission regs as well.<br /><br />Just some more off the wall comments from me <br />anyway, have a nice evening all, <br /><br />regards<br /><br />Frank

 

[JS2]

Re: Give your opinions on attached 2 vs. 4 stroke article

DigDug - yes !

 

[Admin5]

Re: Give your opinions on attached 2 vs. 4 stroke article

^

 

[Forktail]

Re: Give your opinions on attached 2 vs. 4 stroke article

I think the point of the article is being overlooked. Its not really a 2-stroke vs. 4-stroke issue. It's more of a "kudos" for the 2-stoke technology, being able to meet the emmissions that only 4-strokes were thought to be capable of. <br /><br />The point is that the tree huggers and greenies have a misconception of the 2-stroke, and would like to rid the world of all of them. Well, surprise! The greenies have failed. 2-stroke technology can cut the mustard too.<br /><br />But there are some points, and some disadvantages/advantages to both designs.<br /><br />The life span of a 2-stroke engine is shorter. Friction parts like crank bearings and piston rings can only be lubricated via residual oil that is being mixed with the fuel and happens to spread throughout the engine. Of course the 2-stroke oil lubricates different, because it is dilluted with fuel and must also be burned with the fuel. It's hard to beat a bath of multi-grade motor oil for long life engine lubrication.<br /><br />2-strokes are more susceptible to fuel/air inputs and exhaust tuning. Rich and lean conditions can exist easily, and consistancy throughout the rpm range is difficult. Direct injection 2-strokes are a begining, and variable exhaust features (on 2-stroke motorcycles and snowmobiles) help. As one poster mentioned above, it takes quite a bit of complexity (and parts) to make a 2-stroke run like a 4-stroke. 2-strokes are absent of a valve train which would allow them to do so. Because of fuel scavaging and the lubrication needs of the 2-stroke, its advancement is primarily limited to fuel delivery technology, however so simple the engine itself may be. The primary advantage of the 2-stroke is power to weight ratio and the fact that 2-strokes can run higher rpm (rpm equates to horsepower). 2-strokes offer good power and torque in a lightweight package. If a little bit more weight matters to you, and you like zippy punch not caring about noise and endless smooth, clean idles, then the 2-stroke is for you. But I think for most consumers, the 4-stroke has more to offer. I'm totally impressed with them and will never go back.<br /><br />4-stroke technology is advancing too, and it'll be hard for the 2-stroke to keep up. Emissions are only going to get tougher. Some have mentioned that a light weight 4-stroke means an unreliable or short-lived 4-stroke. This is not necessarily true given todays technology in alloys, engine design, and fuel injection. Several engine manufacturers are testing camless 4-stroke designs. The valves operate electronically or hydraulically, and rpm can be greatly increased.<br /><br />I'll take nothing but a 2-stroke in my dirt bike and snowmobile. I love their light-weight power. Weight is a significant issue here. But in my boats where 50 lbs and 0-60 mph doesn't matter, the advantages of the 4-stroke far exceed those of the 2-stroke. The 4's are truely a pleasure to own, operate, and maintain.<br /><br />They each have their place. We're lucky to have our choice in marine. I say "kudos" to the 2-strokes though.

 

[Skinnywater]

Re: Give your opinions on attached 2 vs. 4 stroke article

Plain simple fact of the matter is. On many waters in the state of California your 2 stroke powered boat will have to stay on the trailer.

 

[seahorse5]

Re: Give your opinions on attached 2 vs. 4 stroke article

One thing about pollution is that they want to limit carbon monoxide (CO) output. On 4 strokes, that means catalytic converters, 2 strokes, direct injected motors already meet the proposed specs. Not only that, the total of hydrocarbons, oxides of nitrogen, and carbon monoxide emissions are lower than on 4 strokes, including the 3-star 225 Honda outboard, and a lot better than the 225 4-stroke Yamaha. That is one of the reasons that Lake Tahoe replaced their Hondas and Yamahas with Evinrude FICHTS last year.

 

[FlyBoyMark]

Re: Give your opinions on attached 2 vs. 4 stroke article

Called all the big Merc dealers from Miami to Jupiter Florida to find a 60 hp short shaft Merc 2 cycle. They all said they called Merc and all 2 cycle except for Optimax and 25 hp or less has been DISCONTINUED! Hmmmmm...... the price on 60 hp 2cycle is $3,600.00 bucks cash and the price on the 4 cycle is $4,300.00 bucks.....Hmmm typical 5% corporate net profit....Hmmmmm....why would "I" as a Merc manufacture want to sell evil polluting products for less gross profit? Hmmmmm.......It's amazing how mass merchandising can work with the environmentalist to (4) stroke you out of your money!!!!<br /> Quote from one of my earlier post(and this is not 4 cycle bashing!):<br /> ......I think the manufactures are testing the waters in this size(4 cycle)....stern drive units might be a better choice in this class. Merc Optimax units are meeting all the emmission standards and making more torque and Hp than 4 cycle counter parts with less weight. REMEMBER...the purpose of an outboard is first; COST then WEIGHT AND THEY HAVE ALL GOTTEN AWAY FROM THAT! So why would you want an outboard that cost $16,000.00 bucks and takes up the whole transom and gets in the way when you can have a nice quite stern drive for half the cost and all the weight under the floor and out of the way?Example; Jus' went to look at a big Mako 31' with cuddy, the whole ?ss end of the boat was two big Merc 250's effectively blocking any serious offshore fishing usage. In addition, they are fuel hogs. Now lets put a single 502 cu. inch 400-500 hp stern drive in. we've saved weight fuel and space and they are cheaper to fix. AND not to mention the engine cost too........I love outboards but lets remember what the REAL purpose of them was and is..... <br />

 

[rwise]

Re: Give your opinions on attached 2 vs. 4 stroke article

Here is my $.02. I don't really care about speed, I fish. I don't like the smoke that a lot of 2 cycle engines put off. I like clean water. I just don't see what the "DFI" can do for oil going through the engine. I would like to see more mfg's doing fuel/electric combo. Though it has a long way to go if we don't start cleaning up our world who will!<br /><br />Richard

 

[FlyBoyMark]

Re: Give your opinions on attached 2 vs. 4 stroke article

rwise....ya know ya can use sails or oars, electric motors use batteries that pollute with lead. And what about all the used crankcase oil from those 4 strokes, jus' full of all those nasty deposits from hours and hours of engine usage.......

 

[beachcraft]

Re: Give your opinions on attached 2 vs. 4 stroke article

My $.02 opinion. <br />I had a outboard, then I switch to the I/O.<br />The reasons are<br />1- I like fishing and crsuising slowly around the channel.<br />2- I don't like to pollute the water that all my fishes will live in.<br />3- No problem w/ I/O for idling all day long.<br />4- No bad smell and noise during boating for scenery.<br />5- Consumming less gas.<br />6- Good new 2/4 cycle outboard engine is very expensive.<br />7- I/O last longer.<br />8- Few extra mile per hour for speed is not important to me.<br />9- 4 cycle outboard technology is still new. <br /><br />I will wait until the 4 cycle engine is more mature/less expensive,<br />then I will consider.<br /><br />

 

[enn]

Re: Give your opinions on attached 2 vs. 4 stroke article

4 strokes have a huge potential for additional improvements as an OB - (ad of catalytic converter direct injection etc)<br /><br />One more thing - no 2 stroke OB has a "good" lubrication system - only oildrops have to lubricate it - a 4 stroke is presure lubricated and it is a much more reliable system. There are plenty of lubrication (and additional cooling) under load.<br /><br />Some of the blown DFI 2 Stroke OBs are due to the fact that they limit the flow of lubrication oil to reduce emissions - these problems do not exist on 4 strok pressure lubricated OBs.<br /><br />2 strokes will be on the market for a long time yet - but i am shure 4 strokes are going to winn the battle just as they did on Aircraft motors and on Cars.

 

[Franki]

Re: Give your opinions on attached 2 vs. 4 stroke article

Well, I don't know, but I think that both methods still have merit..<br /><br />at the high performance level, we know that a 2 stroke is smaller then a four for the same power levels.. (see the motocross metioned above.)<br /><br />Now if you somehow get effective tuned exhaust on a two stroke outboard, (which noone has really done yet) you will end up with an engine with half the capacity of a four stroke, but the same power... add DFI to that and you get even more difference, and the expansion chamber scavanging also improves the emmisions as well.<br /><br />I think you will see many variants of the 2 stroke before they fade away, (if they ever do)<br /><br />take this for example, a turbo or supercharger removing the need for crankcase compression altogether,, then what do you have?<br /><br />a crankcase full of oil of course.. and the power output could be increased even further as you could really bump up the boost and doing that would get even more of the old burnt mixture out as you wouldn't need transfer ports to do it..<br /><br />So just keep in mind that you can go in alot of different directions with both engine types..<br /><br />can you imagine a 1 liter 2 stroke engine, <br />with a sump and normal (4stroke style) lube system, supercharged (maybe a whipple charger) for more power and efficiency) AETC, (auto exhaust timing control) and tuned expansion chamber exhaust system... and DFI.<br />you could get an engine like that outputting 225HP and reving safely up to 10,000rpm, and since its only 1 liter, it would have unbeatable fuel ecomomy and emmissions, and no oil usage beyond what 4 strokes have?<br /><br />Guess what? we have just gotten the benefits of both 2 and 4 strokes in one motor..<br /><br />superchagers are small as nowdays, and don't have that many moving parts, (most of which have a rotary motion as well, which lessons reciprocal weight.) DFI is already here. combine it all and you have a 2 stroke that would be very hard for a four stroke to ever catch up to.<br />Think about it, every piece of technology in that motor already exists, they just have yet to combine them effectively.<br /><br />and a couple of other points I'd like to make..<br />1. If two stroks don't last as long, why are these lists just filled with people running 1950-70 2 stroke outboards???? can't be that bad, many haven't been rebuild and are still runnin strong.<br />2. As I understand it, the problem with "no camshaft" engines, is that hydrolics or electrics are having trouble opening and closing a valve with enough force to seal at 100+ times a second, so at present, the motors will rev less rather then more.. I had the idea of doin that years ago.. and thats what I discovered back then, nothing at that level of technology was capable of doing it. still, its a fantastic idea if someone figures out a reliable way of doing it.<br /><br />regards<br /><br />Frank

 

[FlyBoyMark]

Re: Give your opinions on attached 2 vs. 4 stroke article

Franki...some of the big and small outboards for years have used tuned exhaust pipes, they are inside the motor leg and made of S.S. steel and I have repaired many of them when they crack. There are 2 cycle engines with oil in the crank case with a pressure lubrication system and they are direct injection;<br />DETROIT DEISELS..........SO it CAN be Done<br />