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Old 01 July 2014, 10:42   #1
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Are 4 strokes starting to win ?

I admit it, i love 2 strokes. They are simple and light and I really think they compliment small ribs and sibs better than a 4 stroke.

But then a question by a newbie made me look at the tech specs for the new small Selva outboards.

The 9.9 4 stroke weighs just 30kg, which is 6kg lighter than the Yamaha 2 stroke and only 4kg heavier than the class leading Tohatsu 9.8 2 stroke.

So have small strokes turned a corner, will we see the 15hp start to come down from the 40kg range in the near future ?
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Old 01 July 2014, 11:08   #2
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The 9.9 4 stroke weighs just 30kg, which is 6kg lighter than the Yamaha 2 stroke and only 4kg heavier than the class leading Tohatsu 9.8 2 stroke.
Yes but for that extra 6kg you can have a 15hp 2 st yam (36kg)
No point comparing with the smaller HP from the same block!
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Old 01 July 2014, 11:37   #3
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And it's not all about weight.

2 stroke produce a power stroke twice as often so have better holeshot.
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Old 01 July 2014, 12:13   #4
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My Honda bf50 has an equally impressive holeshot as my previous Yamaha 40 Autolube. I think there are pros and cons for both 2 stroke and 4 stroke. For some 2 stroke is the better option, but I'm happy with my 4 stroke on a 4 metre rib.
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Old 01 July 2014, 12:21   #5
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On Sunday I took off from a standing start alongside "zestorer". A Honda BF50 4s against a Tohatsu 50 2s, on two identical ribs (SR4's). Zestorer was 2 up, I was single handed (but I'm fatter that the occupants of Zestorer). Both ribs seemed roughly equal on acceleration. So yes the 2 stoke would have won if it had been single handed but the difference is marginal (unless James wasn't really trying, which could be true).
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Old 01 July 2014, 12:46   #6
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my 2004 40 yam four stroke outran a mid 90s Mariner 40 two stroke (just) SR4 on acceleration and top speed in my SR4.
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Old 01 July 2014, 12:56   #7
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Yes but for that extra 6kg you can have a 15hp 2 st yam (36kg)
No point comparing with the smaller HP from the same block!
Yep, its a fair point. But the 15hp, 4 stroke Yamaha is now just 39kg, down over 12kg on its lardyarse previous version.
So they are getting a lot closer.
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Old 01 July 2014, 13:24   #8
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4 Stroke all the way! Environmental reasons should be the number 1 reason for them. I feel guilty every time I start my 2 stroke up and see a sheen of oil on the water.

I was reading another thread where the guy has to have a 4 stroke in order to run it on local lakes in Portugal. Some of our cleanest lakes here in the USA have banned 2 strokes also. It is a trend that will continue.

Of course the direct injection 2 strokes are completely different, but even they barely meet the emission standards put forth today.
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Old 01 July 2014, 13:37   #9
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4 Stroke all the way! Environmental reasons should be the number 1 reason for them. I feel guilty every time I start my 2 stroke up and see a sheen of oil on the water.

.
But if thats your logic, surely your boat should have a stick, scraps of string and flappy bits instead ?
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Old 01 July 2014, 13:44   #10
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I've just gone the other way.....

I had a 2003 Suzuki DF50 on a 4.5m Avon Adventure, I now have a 2003 Tohatsu M50D2 on a SR4

Both in approx same condition and hours.

Suzuki was quiet, smooth and very economical. It loved doing 2k revs and pootle up rivers at 6knts comfortably. The hole shot was more of a relaxed affair, and at WoT I'd hit about 28kts

The Tohatsu delivers it's power completely differently, it's instant but very on or off...! It hates doing anything under 3k, and is slightly less economical than the Suzuki......but it puts a grin on my face that the Suzuki didn't..!!! It also hit 34knts with two up on Sun, without really pushing the hull.

Nothing we all didn't know really.?

However....I did have go on Tigga, and was quite surprised with the holeshot.

Would I swop..........hummmm...........nah. but on a bigger boat I'd prob want to go 4st.
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