Fuel Economy 90hp 2 Strokes

[J S]

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.

Thanks

James

[dctucker]

James,

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)

[PeterR]

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

[Swifty]

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.

[BogMonster]

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.

[Mouldy]

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.

[fast fred]

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.