Phildave
01-07-2009, 07:41 AM
Have chance to buy 35 foot Simpson Woodsong with 2 30hp Mariner 2 stroke. Good choice. Any advice?
View Full Version : better choice 2 stroke or 4 stroke?
Frosty
01-07-2009, 08:16 AM
Where does the 4 stroke bit come in?
CDK
01-07-2009, 01:39 PM
Maybe 2 times 2 stroke = 4 stroke(s)?
StianM
01-07-2009, 02:56 PM
If the boat is a good buy take it.
Dos it really mater what engines is on it?
If I was to buy new engines I would go for Evinrude two strokes.
They comply with all new regulations and two strokes has few moving parts compared to a four stroke and weigh a few kg less.
Dos it really mater what engines is on it?
If I was to buy new engines I would go for Evinrude two strokes.
They comply with all new regulations and two strokes has few moving parts compared to a four stroke and weigh a few kg less.
messabout
01-28-2009, 05:05 PM
A 35 foot boat with total 70 HP. Not enough power if it is a planing boat. Unecessary excess of power if it is a strictly displacement type. If displacement type then big slow turning props are generally the best option. That means that lower unit gear ratio needs some thought. For economy, the 4 stroke is a better option. Two stroke engines are signifigantly lighter in weight than the 4 stroke counterparts. Either type is reliable enough if maintained satisfactorily.
sandhammaren05
05-07-2009, 05:20 AM
2 stroke motors are much lighter and smaller, and accelerate about twice as fast as a 4 stroke. I personally wouldn't own a 4 stroke, they came into existence only to meet environmental rules, but the new Evinrude direct injected 2 strokes are cleaner and better. The Mariner 30 is probably a Yamaha, a very good motor. But as stated below, with only 60 hp you're way underpowered. I'd take a 250 (or, if you want insurance in case a motor goes south far from shore, a pair of 150s).
Have chance to buy 35 foot Simpson Woodsong with 2 30hp Mariner 2 stroke. Good choice. Any advice?
Have chance to buy 35 foot Simpson Woodsong with 2 30hp Mariner 2 stroke. Good choice. Any advice?
mwatts
08-21-2009, 09:17 AM
2 stroke motors are much lighter and smaller, and accelerate about twice as fast as a 4 stroke. I personally wouldn't own a 4 stroke, they came into existence only to meet environmental rules.
There's a few strong statements for ya.
In the first place, the time that 2 strokes where twice as fast to accelerate, is really quite a few years behind us. In fact a 50hp 2-stroke has never been twice as fast as a 50hp 4-stroke.
As far as size is concerned: the powerhead is usually just as fat, maybe at the most 10% lower in most cases (depends a bit on the brand).
2 strokes usually ARE lighter, you are right about that. Sometimes 30%.
Another big reason for people to by 4-strokes, is fuel economy. Here in the Netherlands, we can't believe the complaints US citizens are making about fuel prices! If you are feeling sorry for yourselves because you have to pay US $2,51 for a gallon of fuel, come over here where you can pay US $ 7,59 a gallon ;)
There's a few strong statements for ya.
In the first place, the time that 2 strokes where twice as fast to accelerate, is really quite a few years behind us. In fact a 50hp 2-stroke has never been twice as fast as a 50hp 4-stroke.
As far as size is concerned: the powerhead is usually just as fat, maybe at the most 10% lower in most cases (depends a bit on the brand).
2 strokes usually ARE lighter, you are right about that. Sometimes 30%.
Another big reason for people to by 4-strokes, is fuel economy. Here in the Netherlands, we can't believe the complaints US citizens are making about fuel prices! If you are feeling sorry for yourselves because you have to pay US $2,51 for a gallon of fuel, come over here where you can pay US $ 7,59 a gallon ;)
sandhammaren05
08-22-2009, 09:37 AM
Check out the APBA speed records for the 1970-1980 era Classes SD and DP, now defunct, and show me a 4 stroke 50 that will run like that. I live mainly in Austria and rebuild 1980s era 2 stroke OMCs for personal use and resale on the Baltic Coast, in case you want a good motor instead of an overweight piece of lumbering 4 stroke pot metal. We offer 15s, 25s and 35s for sale.
Yellowjacket
08-22-2009, 10:57 PM
Don't get me wrong, I am a big fan of 2 strokes and probably wouldn't consider a 4 stroke engine for anything I want to do with an outboard...
But.. 2 Strokes have on Achilles heel and that is scorching and lack of lubrication near the exhaust port. This can eventually result in ring failure and/or bore scuffing in this area and it is, generally speaking the life limiting part of a two stroke if you run it real hard.
If you don't run them really hard they will last forever, but if you take advantage of that higher power to weight ratio there is a good chance that they won't last as long as a four stroke. I can't tell you the number of 2 strokes that I've seen with bore scuffing near the exhaust port and stuck rings.... Yes there are fewer parts and less to go wrong, but you don't buy a 2 stroke for long life, you buy it for performance.
My experiece is old, but my father in law had to rebuild the power head of his 200 hp Johnson a few years ago for just this reason, so it would appear that some things never change. Maybe newer generation lubricants and newer materials can address this issue, so if I am wrong here somebody enlighten me.
But.. 2 Strokes have on Achilles heel and that is scorching and lack of lubrication near the exhaust port. This can eventually result in ring failure and/or bore scuffing in this area and it is, generally speaking the life limiting part of a two stroke if you run it real hard.
If you don't run them really hard they will last forever, but if you take advantage of that higher power to weight ratio there is a good chance that they won't last as long as a four stroke. I can't tell you the number of 2 strokes that I've seen with bore scuffing near the exhaust port and stuck rings.... Yes there are fewer parts and less to go wrong, but you don't buy a 2 stroke for long life, you buy it for performance.
My experiece is old, but my father in law had to rebuild the power head of his 200 hp Johnson a few years ago for just this reason, so it would appear that some things never change. Maybe newer generation lubricants and newer materials can address this issue, so if I am wrong here somebody enlighten me.
powerabout
08-23-2009, 01:13 AM
Was that a cross flow or looper 200?
Yellowjacket
08-23-2009, 10:40 AM
Not sure, it was older, 1995 vintage...
ondarvr
08-24-2009, 12:33 PM
Stuck rings and scored cylinders are not a design flaw, its a sign of poor maintenance, setup, or possibly another type of failure. Rarely do outboards wear out, they die from dirty carbs and/or a lack of cooling (neglect), plus the wrong prop.
Yellowjacket
08-24-2009, 01:37 PM
Frankly most outboard motors don't get used enough to wear out in any way shape or form. They see a couple of hours a week in most applications and in these cases are lucky to see a hundred hours a year. Unless you are running the heck out of your boat you aren't likey to ever wear one out.
But eventually everything wears out. What I am saying is that you will most likely see wear and carbon buildup in the rings of an outboard that has been consistently run hard. There is essentially no cooling in this area of the cylinder (as opposed to the rest of the cylinder that has a water jacket around it) so this is where you start to see coke buildup in the rings and after a while the hard carbon buildup wears the cylinder. Take apart any two stroke that has been run a lot and you will see carbon buildup in the rings and scuffing in the bore area around the exhaust port. That is where the wear out first, that's all.
The engines I'm talking about weren't modified in any way, they were run the way the factory delivered them, and near as I can tell were properly maintained. Like I said I'm a two stroke fan, and two strokes have a better power to weight ratio than a 4 stroke, but if you use all of it, it won't last as long, at least that has been my experience.
But eventually everything wears out. What I am saying is that you will most likely see wear and carbon buildup in the rings of an outboard that has been consistently run hard. There is essentially no cooling in this area of the cylinder (as opposed to the rest of the cylinder that has a water jacket around it) so this is where you start to see coke buildup in the rings and after a while the hard carbon buildup wears the cylinder. Take apart any two stroke that has been run a lot and you will see carbon buildup in the rings and scuffing in the bore area around the exhaust port. That is where the wear out first, that's all.
The engines I'm talking about weren't modified in any way, they were run the way the factory delivered them, and near as I can tell were properly maintained. Like I said I'm a two stroke fan, and two strokes have a better power to weight ratio than a 4 stroke, but if you use all of it, it won't last as long, at least that has been my experience.
ondarvr
08-24-2009, 09:27 PM
Running hard at a higher RPM can actually clean out some of the gunk, over propping and never using a decarb type product like is recommended leads to coking and stuck rings. I've raced 2 strokes for the last 40 years and these problems exist in poorly setup engines. If there's a problem this is where it shows up first, its not something that happens on its own and creates other issues.
I'm not a fan or hater of either type and only own 2 strokes, but my next purchase may be a 4-S.
I'm not a fan or hater of either type and only own 2 strokes, but my next purchase may be a 4-S.
mwatts
08-25-2009, 05:06 AM
Check out the APBA speed records for the 1970-1980 era Classes SD and DP, now defunct, and show me a 4 stroke 50 that will run like that. I live mainly in Austria and rebuild 1980s era 2 stroke OMCs for personal use and resale on the Baltic Coast, in case you want a good motor instead of an overweight piece of lumbering 4 stroke pot metal. We offer 15s, 25s and 35s for sale.
Actually, I owned a 1991 Johnson 50HP 2S for quite some time. It is still running (a close friend owns it now) and it's a fast and powerful engine; pulls 2 wakeboarders or a mono skier with 3 people in the boat without any problem. And it ran on virtualy anything, as long as it was more than 60 octane. :) It not being so "delicate" can be a welcome thing in some area's.
But 4 strokes have come a long way since then, as far as power / weight ratio is concerned.
If I would have to choose now, I would choose a 4S, simply because I don't sail at WOT ever anymore. If you never open the throttle further than 2/3 anyway, 4S is a smarter choice.
Actually, I owned a 1991 Johnson 50HP 2S for quite some time. It is still running (a close friend owns it now) and it's a fast and powerful engine; pulls 2 wakeboarders or a mono skier with 3 people in the boat without any problem. And it ran on virtualy anything, as long as it was more than 60 octane. :) It not being so "delicate" can be a welcome thing in some area's.
But 4 strokes have come a long way since then, as far as power / weight ratio is concerned.
If I would have to choose now, I would choose a 4S, simply because I don't sail at WOT ever anymore. If you never open the throttle further than 2/3 anyway, 4S is a smarter choice.
Wynand N
08-25-2009, 07:49 AM
Luckily we do not have the emission control issues that are law in many countries, iow, we can still enjoy our two strokes.
I have the local Tohatsu outboard agency and most engines sold are two strokes. Today's two stroke do not smoke (not at all in cases) as the older stinkpots and also run quite silently. The new Tohatsu TDLI's are quite a gas and comply to all international emission standards and will run the pants off any equivalent sized four stroke.
Four strokes are expensive to keep. You have oil changes, filters and cam belts to look after and usually when something goes wrong on them, its mayor and expensive. My little backup 2S engine is usually tucked into a hole in the boat with no fear of oil spilling out, and or fouling the valves by doing so. And as said, they are not only more complicated but also heavier.
The new generation two strokes such as the Tohatsu TDLI's, are just as quite as four strokes and basically uses the same amount of fuel.
Here are some figures on the fuel consumption quoted by Tohatsu.
Two stroke 30hp - 13.0 l/h (3.4 g/h) at WOT (conventional 2S motor)
Four Stroke 30hp - 10.4 l/h (2.8 g/h) at WOT
Two stroke TDLI 40hp - 15.2 l/h (4 g/h) at WOT (latest technology)
Not much between them all although the TDLi is a 40hp. But one has to look at the bigger picture. The purchase price of a 4S can easily be about 30% more than conventional 2S. Add to that the service charges as they are much more expensive to maintain and compare running costs over 5 years ownership and one will find that 2S motors are actually cheaper to run than their 4S cousins. And they are more responsive and faster out of the hole when needed.
My 2 cent worth
I have the local Tohatsu outboard agency and most engines sold are two strokes. Today's two stroke do not smoke (not at all in cases) as the older stinkpots and also run quite silently. The new Tohatsu TDLI's are quite a gas and comply to all international emission standards and will run the pants off any equivalent sized four stroke.
Four strokes are expensive to keep. You have oil changes, filters and cam belts to look after and usually when something goes wrong on them, its mayor and expensive. My little backup 2S engine is usually tucked into a hole in the boat with no fear of oil spilling out, and or fouling the valves by doing so. And as said, they are not only more complicated but also heavier.
The new generation two strokes such as the Tohatsu TDLI's, are just as quite as four strokes and basically uses the same amount of fuel.
Here are some figures on the fuel consumption quoted by Tohatsu.
Two stroke 30hp - 13.0 l/h (3.4 g/h) at WOT (conventional 2S motor)
Four Stroke 30hp - 10.4 l/h (2.8 g/h) at WOT
Two stroke TDLI 40hp - 15.2 l/h (4 g/h) at WOT (latest technology)
Not much between them all although the TDLi is a 40hp. But one has to look at the bigger picture. The purchase price of a 4S can easily be about 30% more than conventional 2S. Add to that the service charges as they are much more expensive to maintain and compare running costs over 5 years ownership and one will find that 2S motors are actually cheaper to run than their 4S cousins. And they are more responsive and faster out of the hole when needed.
My 2 cent worth
mwatts
08-25-2009, 08:17 AM
It's not quite fair stating oil changes as one of the maintenance costs for 4 strokes, while completely ignoring the fact that the oil that is mixed into the fuel of 2 strokes add's about 10% on top of the fuel price.
As we say in Holland: that's comparing appels and pears. ;)
Besides that, the difference in fuel consumption between 2S and 4S is the smallest at WOT. At 50% throttle, the differences will be bigger. And engine's aren't run at WOT all the time in real life, so comparing WOT consumption, is biassing the 2S.
I'm not saying 4 strokes are always better. Like I said, I owned a 2S for ages, on a small ski boat, where it excelled. But for quiet cruising in a small displacement boat, a 2S does not even come into my consideration.
As we say in Holland: that's comparing appels and pears. ;)
Besides that, the difference in fuel consumption between 2S and 4S is the smallest at WOT. At 50% throttle, the differences will be bigger. And engine's aren't run at WOT all the time in real life, so comparing WOT consumption, is biassing the 2S.
I'm not saying 4 strokes are always better. Like I said, I owned a 2S for ages, on a small ski boat, where it excelled. But for quiet cruising in a small displacement boat, a 2S does not even come into my consideration.
sandhammaren05
08-25-2009, 01:52 PM
Loopers must be rebuilt more often than cross flow but are far more efficient, less fuel lost through exhaust. I rebuilt my racing powerheads (loopers) once/season but would have been able to run one for years with ordinary use. If you want top performance then there's a price. Oars, e.g., can last for a lifetime ... .
Don't get me wrong, I am a big fan of 2 strokes and probably wouldn't consider a 4 stroke engine for anything I want to do with an outboard...
But.. 2 Strokes have on Achilles heel and that is scorching and lack of lubrication near the exhaust port. This can eventually result in ring failure and/or bore scuffing in this area and it is, generally speaking the life limiting part of a two stroke if you run it real hard.
If you don't run them really hard they will last forever, but if you take advantage of that higher power to weight ratio there is a good chance that they won't last as long as a four stroke. I can't tell you the number of 2 strokes that I've seen with bore scuffing near the exhaust port and stuck rings.... Yes there are fewer parts and less to go wrong, but you don't buy a 2 stroke for long life, you buy it for performance.
My experiece is old, but my father in law had to rebuild the power head of his 200 hp Johnson a few years ago for just this reason, so it would appear that some things never change. Maybe newer generation lubricants and newer materials can address this issue, so if I am wrong here somebody enlighten me.
Don't get me wrong, I am a big fan of 2 strokes and probably wouldn't consider a 4 stroke engine for anything I want to do with an outboard...
But.. 2 Strokes have on Achilles heel and that is scorching and lack of lubrication near the exhaust port. This can eventually result in ring failure and/or bore scuffing in this area and it is, generally speaking the life limiting part of a two stroke if you run it real hard.
If you don't run them really hard they will last forever, but if you take advantage of that higher power to weight ratio there is a good chance that they won't last as long as a four stroke. I can't tell you the number of 2 strokes that I've seen with bore scuffing near the exhaust port and stuck rings.... Yes there are fewer parts and less to go wrong, but you don't buy a 2 stroke for long life, you buy it for performance.
My experiece is old, but my father in law had to rebuild the power head of his 200 hp Johnson a few years ago for just this reason, so it would appear that some things never change. Maybe newer generation lubricants and newer materials can address this issue, so if I am wrong here somebody enlighten me.
powerabout
08-25-2009, 02:14 PM
dont forget the pollution your waste oil and filter makes from your 4stroke not to mention all the extra pollution in trying to make the thing with a gazillion more parts and if it goes wrong will probably be a throw away due to the cost like everything else Japanese.
View Full Version : better choice 2 stroke or 4 stroke?
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