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Old 29 May 2006, 22:17   #1
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Differences between 2-stoke and 4 -stroke?

Hi all

I am looking to get my first rib (5.5m to 6.5m) in the near future...Can anyone tell me the main differences between the two and four stroke engines..(ie noise, servicing, performance, durability...etc...)

Since the RIB will be over 5.5m I prefer to have at minimum of 70-80BHP.

The rib will be used for cruising, diving and fishing in the Med.

thanks in advance


E
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Old 29 May 2006, 23:20   #2
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In a nutshell:

(Traditional) 2 strokes: lighter, noisier, thirstier, cheaper to buy, easier to service, better performance.
4 strokes: quiter, cheaper to run, more expensive to buy, more expensive to service, less bottom end performance, heavier.

Although the new "computerised" 2 strokes are more like 4 strokes in terms of fuel economy.
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Old 30 May 2006, 00:06   #3
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Expanding the cheaper to service side of 2 strokes. That only counts if you can actually service a two stroke. And if its old and playing you up most people can't.
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Old 30 May 2006, 08:34   #4
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If your getting a four stroke make sure you get one with EFi as some of the smaller sizes are still on carbs. This not only improves economy, but in my experience also performance, particularly top end inmproves. Whilst the performance is never going to match a two stroke an EFi four stroke does provide decent performance.
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Old 30 May 2006, 09:28   #5
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Or punch 2 stroke/ 4 stroke into 'Search', it'll give you hours of informative reading.
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Old 30 May 2006, 10:13   #6
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Hi,
I've got an E-TEC 40HP, it's a high pressure direct injection two stroke. Compared to 4 strokes, they are lighter (although mine isn't really as it's a restricted 60HP so compares to a 40HP four-stroke with a 40HP block) and more economical than a four stroke (only slightly more economical) although can be a tad louder. Fuel consumption at idle is ridiculous, it uses virtually no fuel to idle so yould be perfect for dive boats etc. where a lot of time is spent at low revs waiting on divers surfacing. They are also cheaper to service, mine doesn't need any servicing till 300hrs/3years (although personally, I'll take it in and get them to give it a quick once over every year). It also winterises itself (all you need to do is press some buttons and add fuel conditioner to the fuel (£5 a bottle ish). The major down side is that they are more expensive than traditional two strokes, but I found my fuel consumption almost halving, so I'm making a good saving there (and increased my range too!)

Cheers,
Fraser
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Old 30 May 2006, 17:32   #7
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Thanks guys

you have been most helpfull
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Old 30 May 2006, 17:44   #8
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My DF140 Suzuki cost me nearly £450 for its 200hr service a few weeks back. I am not sure what this compares to other peoples DF140 servicing, or Optimax owner service costs.

-Alex
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