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Old 13 December 2007, 09:31   #1
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two strokes cool or not?

what are your thoughs on two stroke engines. me personaly i like them. from what i know about outboards the only differances between two and four strokes are four strokes save fual and are very quiet. two strokes are load and are not as good on fual aconamy but the do go faster and can cope with more than what a four stroke can. what are your thoughs
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Old 13 December 2007, 23:13   #2
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what are your thoughs on two stroke engines. me personaly i like them. from what i know about outboards the only differances between two and four strokes are four strokes save fual and are very quiet. two strokes are load and are not as good on fual aconamy but the do go faster and can cope with more than what a four stroke can. what are your thoughs

It sure sounds like someone's trolling for a response, or someone who has not followed outboard motor advances for the last few years and still thinks of carbureted two-strokes as state of the art .

Read the manufacturer's literature on direct injected 2 strokes, their performance, fuel economy, emissions, and how one (Evinrude) is in the same class as 4 strokes in the "quiet" dept.
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Old 14 December 2007, 03:30   #3
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It sure sounds like someone's trolling for a response, or someone who has not followed outboard motor advances for the last few years and still thinks of carbureted two-strokes as state of the art .

Read the manufacturer's literature on direct injected 2 strokes, their performance, fuel economy, emissions, and how one (Evinrude) is in the same class as 4 strokes in the "quiet" dept.
ow right but im not a huge lover of everude engines. i prefer yamaha
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Old 14 December 2007, 04:06   #4
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xr2 very cool
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Old 14 December 2007, 04:13   #5
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two strokes are load and are not as good on fual aconamy but the do go faster

If you run "flat out" all the time the fuel economy difference will be almost non existent. Bottom line is to get X Horsepower at the shaft you need to burn a certain amount of fuel to to get that energy to turn the prop....

If you spend a lot of time pootling around (e.g. rescue boat for a dinghy club, fishing etc ) then yes, 4- strokes generally use less, but that's only because most 4-stroke outboards are built to get round the new Emmissions regs, and the engine management / fuel injection is in there with the prime reason to reduce fuel consumption - just look at modern diesels in cars - 10 years ago they sounded like tractors - now with Common Rail injection technology & engine management control they're as smooth & quiet as petrols.


Faster is a big scary equation involving popellor pitch, engine torque, boat shape & weight etc etc etc. A 2- stroke with the wrong prop will be left standing by a smaller 4- stroke on the same boat if it's got the wrong set of blades.

I've had a series of (relatively) small old 2- strokes simply because I don't need a laptop to self service them and can buy them & spares at reasonable cost. If I'm on a rescue boat mission I'd rather have a 4 - stroke so I could hear mself think since a lot of time is spent not going anywhere fast.


With outboards I don't think you can make easy general comparisons. It all depends on the boat they're on, what you use them for, what your idea of "quiet", "fast" "cheap" etc are, whether you've had a bad experience with a particular make..... One man's dream engine is the next man's worst nightmare.

2- stroke works for me tho'
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Old 14 December 2007, 08:58   #6
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If you run "flat out" all the time the fuel economy difference will be almost non existent. Bottom line is to get X Horsepower at the shaft you need to burn a certain amount of fuel to to get that energy to turn the prop....

If you spend a lot of time pootling around (e.g. rescue boat for a dinghy club, fishing etc ) then yes, 4- strokes generally use less, but that's only because most 4-stroke outboards are built to get round the new Emmissions regs, and the engine management / fuel injection is in there with the prime reason to reduce fuel consumption - just look at modern diesels in cars - 10 years ago they sounded like tractors - now with Common Rail injection technology & engine management control they're as smooth & quiet as petrols.


Faster is a big scary equation involving popellor pitch, engine torque, boat shape & weight etc etc etc. A 2- stroke with the wrong prop will be left standing by a smaller 4- stroke on the same boat if it's got the wrong set of blades.

I've had a series of (relatively) small old 2- strokes simply because I don't need a laptop to self service them and can buy them & spares at reasonable cost. If I'm on a rescue boat mission I'd rather have a 4 - stroke so I could hear mself think since a lot of time is spent not going anywhere fast.


With outboards I don't think you can make easy general comparisons. It all depends on the boat they're on, what you use them for, what your idea of "quiet", "fast" "cheap" etc are, whether you've had a bad experience with a particular make..... One man's dream engine is the next man's worst nightmare.

2- stroke works for me tho'
thanks fot that il keep it in mind. the part of this post was the prop iv always been a fan of getting the bigest size propella as i can. what i found was the bigger the prop the less revs you need to run your engine at.
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Old 14 December 2007, 10:41   #7
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thanks fot that il keep it in mind. the part of this post was the prop iv always been a fan of getting the bigest size propella as i can. what i found was the bigger the prop the less revs you need to run your engine at.

It's bad to make your engine labour. If your Yam isn't making at least 4500 rpm at full throttle you need to go down a couple of inches pitch.
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Old 14 December 2007, 11:22   #8
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Yep, and those 2- stroke yams really don't like going slow or they just oil up!
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Old 14 December 2007, 14:35   #9
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Try doing this with a Four stroke

PS this is a big video so you will need broadband but its definately worth waiting for.


http://runryder.com/rrtv.htm?v=/heli...obby-Watts.wmv
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Old 14 December 2007, 15:34   #10
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Wow that required some coordination
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