fuel usage 90 hp 4st/etec/optimax

[coucho]

Hi guys I am currently looking at purchasing a new boat in the not to distant future and I would to get an idea of what kind of money its gunna cost me to push around. I am looking at something in the plate ally 4.8-5.5m range and would like to power it up using one of the listed options.
I am not looking to start the two vs four war all over I just would like to hear from anyone who has a boat of similar size running any of these engines re what speed she is doing and how much she drinks an hour.
Thanks in avance guys

[FNQCairns]

Well I can give you the top end of fuel costs, I own a traditional 90hp 2st pushing a 6m + a bit pressed tinny, at slow cruise it uses 15l/h and at fast cruise 22L/h both end up in my instance around the same Km/L which is 1.9.

The above is in offshore trim so it is heavy, if out by myself and with a bigger pitch prop change to suit I get a little better than 2.3km/l in good conditions.

My engine on a 5.5 tinny would see nearer to 2.5km/l than 2km/l.

cheers fnq

[Noelm]

it all comes down to. . . . they are all 90HP, they are all "new technology" so they will all use about the same amount of fuel over a range of conditions (like Fishing) some may use a tad less at troll speed, some a bit less at full throttle, but overall, it will be very very close to the same, don't care what brand or operation principal it is, some will be quieter at idle, but at cruise and above, they will be almost the same, so there you go, before all the 2 strokers and 4 strokers get hot under the collar and blow thier proverbial trumpets, that's it in a nutshell.

[disorderly]

I have a 90 E-Tec on a 5.25 stacer..
If I drive for economy I get 2.5km's per litre....if I'm really loaded up,in rough conditions or driving at near WOT for long periods this will drop to around 2km's/L.

Scott(FNQ) what speed do you get at WOT pushing that big tinny?
On my boat WOT is only 56 km/h..

Scott

[STUIE63]

I've got a 5.5 Galeforce with a 90 etec get around the same as scott 2 - 2.5 km/l
Stuie

[FNQCairns]

I have a 90 E-Tec on a 5.25 stacer..
If I drive for economy I get 2.5km's per litre....if I'm really loaded up,in rough conditions or driving at near WOT for long periods this will drop to around 2km's/L.

Scott(FNQ) what speed do you get at WOT pushing that big tinny?
On my boat WOT is only 56 km/h..

Scott

54-56km/h when offshore and heavy but when just me offshore closer to 65km/h.

cheers fnq

[boatboy50]

Hey,

Suzuki 115 Four Stroke (same block as the 90), pushing a 5.3 Polycraft Bowrider.

Uses 12l/h at 4000rpm cruise speed, pulling around 24 knots.

Excellent engine with nothing but praise.

Regards

Darren

[coucho]

Thanks guys
Noelm thanks not really looking for a comparison between usage just want to get an idea of what its gunna cost to run from guys with similar rigs.
Scott (disorderly) and stuie whats your approx. speed when your cruising using 2- 2.5 L/Km

Darren I like the suzuki's and the hondas and the etecs don't really know much about the merc optimax though i guess it will come down to package purchase price ultimately. But I got to admit I am a bit sweet on the suzuki's

be still very interested to hear from someone with an optimax do they have similar fuel usage to the etec?

[coucho]

darren that works out at around 3.7 km/L 12 litre and hour 24 Knots is 2 nm/L
2 nm = to around 3.7 km thats sounds pretty incredible

[STUIE63]

coucho anywhere between 20-25 knots 20kn =2.5km/l 25kn = 2km/l
Stuie

[ozbee]

you really have to take these figures as a minor guide line type of hull amount of boat weight etc if your boat is light go for a smaller cube for horsepower if you have a heavy or deep v or loaded up quite often go for the most cube they may not show the best fuelage figures on light or flat bottom but they will win hands down once a bit of weight is involved . simple fact is four or di two stroke the fuel does not have the ability to escape till after ignition so force is much the same

[Coontakinta]

Coucho, I have a 5m Razerline Eclipse powered by a 90hp Tohatsu TLDI. The tohie is spinning a 14" alloy blade. The razerline has few extras so the weight of the hull maybe a bit over that specified in the broshures anyway, with three up, a full load of fuel, kill tank, and live bait tank also full, I can get a WOT speed of 56km/h. Emptying the the LB tank doesnt make much difference strangley. I'm not certain of exact usage, but the link below might be of some use to you, it shows some pictures I took from my NAVMAN fuel management system at different rpm. Shows speed, ecconomy and fuel usage

http://www.ausfish.com.au/vforum/showthread.php?t=105373&highlight=Tohatsu

Hope you find the info useful, good luck with your purchase.

[coucho]

thanks coonta another option well woth looking into

[fishing111]

Coucho, pulled this off another site, but I think the 90 and 115 are the same size block so may be of some help to you. All details logged for first 100 hrs.



Thought this may interest some of you
I purchased a new 115 hp Mercury Optimax on 23/8/07,and I have just had the 100hr service done
This outboard is used mainly for bottom fishing ,blast out ,drift or anchor ,move around blast back .It does also do trolling and also tows a scallop drege in season
I keep a log for any prospective buyers and this is the result so far
!00 hrs
35 ltrs oil
1003 ltrs 91 oct fuel
979.1n/m
avg 0.976 nm/ltr
I flush engine without running the motor 3 or 4 times then next time flush with engine running
I havent used anything other than water in flushing ,no salt away or similar
I do use the mercury fuel additive recommended
Rob the local Merc mechanic told me that there were no salt crystals in the engine at all and the thermostat looked like it was brand new He never replaced anything on the engine except for new gaskits
Other than a mercury fuel line prolapsing internally and starving the engine of fuel I have had not had a problem with the outboard
In case you are wondering the reason Im writing this is to give credit where it is due ,in the past my father and I have had 2 Mercs and they were rubbish i swore i would not have another .I was talked into this engine and am pleased to say Rob has been vindicated I am totally rapt with this outboard

[marty+jojo]

What ever engine you buy you will get better economy if you throw all ya snapper heads at people;D ;D ;D ;D
sorry, could not help myself.... I still laugh when i think about that.
Classic.
Marty.