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Old 11 December 2006, 10:46   #1
Country: UK - England
Town: N.Wales/Southampton
Make: Zodiac
Length: 3m +
Engine: Honda 15hp
Join Date: Mar 2006
Posts: 449
Fuel Economy 90hp 2 Strokes

What is the difference in fuel economy between a fuel injected 2 stroke and a carbed 2 stroke. I know a carbed engine will be more but how much more in terms in litres per hour. Also has anybody got any fuel figures of a 90hp on a 5-6m rib at crusing speed of the two types to compare. And what do people think are the best makes/models engines out of the two categories to buy second hand around 2-4 years old. To help in a possible future purchase.



J S is offline   Reply With Quote
Old 11 December 2006, 11:18   #2
Country: USA
Town: Marblehead, MA
Boat name: Bouncy Pumpkin
Make: Avon Searider 5.4
Length: 5m +
Engine: Evinrude 90 E-TEC
Join Date: Sep 2004
Posts: 390

I've been doing a lot of digging around for info like this, as I'm ready to repower my 5.4 Searider. For DI 2-stokes, your options are pretty limited: Evinrude E-TEC, Mercury Optimax or Tohatsu/Nissan TLDI. I beleive the E-TEC is a bit more efficient than the Tohatsu. I wrote off the Opti immediately, as it is a porker, quite heavy compared to the other two. That's the same reason I'm not interested in a 4-stroke.

Most of the user reports I've found, indicate an improvement in cruising range/efficiency on the order of 35%-50% depending on use for folks repowering from a carbed 2-stroke to an equivilent E-TEC.

It's tough (nearly impossible) to find a 2-4 year old used one of any of these. I've seen a few E-TECs on eBay (USA) but they sell at a premium, not enough of a discount to justify the lack of warranty IMHO. I've been searching and pondering for several months, and I'll be laying down the cash for a new 90 E-TEC in a few days.

Carbed 2-strokes, 4-6 years old, are easy to find as they're frequently being replaced by newer tech engines (DI 2-stroke or 4-stroke)

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Old 11 December 2006, 14:49   #3
Country: UK - England
Town: Essex/Vendee
Boat name: shockwave,Voluntry 2
Make: Pac 22/ searider5.4
Length: 6m +
Engine: 180hp turbo,yam 90
Join Date: Nov 2004
Posts: 1,010
I can only speak about the ficht 90 it was reliable for me having bought it new.Was at least 40% more economical than carbed engine.The other consideration is do you mind the continuos smell of 2 stroke oil a carb model will give you .Dont get me wrong and I,m sure theirs many of you like me who enjoy the smell of burning Bell Ray 2 stroke oil.But a smoking cold carb outboard stinks.I know your passengers will feel sick.Happy hunting and hope i,ve helped
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Old 17 December 2006, 13:25   #4
Country: UK - England
Town: Nr Faversham, Kent
Boat name: C Rider
Make: Avon
Length: 5m +
Engine: Yam 80
Join Date: Jan 2005
Posts: 479
I run a nineties vintage, 90 Mercury. Still going strong, but compared to other rigs, I use around a third more than a Yamaha 4 stroke 80 for the same journey. Reverse the figures and that would be a 30% saving over my 2 stroke. I suspect an E-tec 90 would be even better.

My Navman with fuel sensor reports I get around 1.2 Nm per Litre at cruising speed. Economy is pretty linear with respect to speed upto around 4000 RPM. After that it starts to fall off to around 0.9 Nm/L.

I run a standard 19" ally prop and max out at 5000RPM = 33Kn light load.
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Swifty is offline   Reply With Quote
Old 17 December 2006, 15:20   #5
Country: Other
Town: Stanley, Falkland Is
Boat name: Seawolf
Make: Osprey Vipermax 5.8
Length: 5m +
Engine: Etec 150
Join Date: Mar 2006
Posts: 3,655
OK mine is a 115 but.....

I don't have a fuel flow meter so hard to say what the economy is exactly but I can say that 20 knots is "not too bad) every additional 5 knots over that near as dammit doubles the fuel consumption! Old tech carbed Johnson V4 and I reckon at WOT you would wipe out the full tank (about 80 odd litres) in less than an hour.
A Boat is a hole in the water, surrounded by fibreglass, into which you throw money...

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Old 18 December 2006, 04:48   #6
Country: UK - Isle of Man
Town: port st mary
Boat name: Orange Peel
Make: Delta
Length: 5m +
Engine: Mercury 90
Join Date: May 2006
Posts: 96
Mercury 90 classic 2 stroke carb on 5.5m Delta, 2 up, full tank and some gear.

Used 40 litres over 40nm on mixed cruising last year in the Irish sea - 30 minutes in choppy @ 15knts, 30 mins cruising@ 25 knts and about another 15 mins at 35knts WOT.
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Old 19 December 2006, 10:29   #7
Country: USA
Town: boston
Boat name: Miss bad 61
Make: Crapko, AKA Mako
Length: 5m +
Engine: OMC Mod50
Join Date: Apr 2006
Posts: 398
when it's all said and done it's about 20% better on fuel at best, 35-50% no chance.
you can make the same power with less Fuel sure, but half, come on.

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