Mercury Optimax

tsunami · 08 May 2001, 09:12

Does anyone have any knowledge of fuel efficiency for an Optimax 200hp.
I fitted a fuel flow meter to my rib at the weekend. My boat is fitted with a 225hp Suzuki. I did a run out to the Mizen and the Fastnet Rock at the weekend and got a shock to see the fuel consumption rates! Cruising at 4000 rpm(33 Knots) the engine was burning 10.5 gph. At full throttle 5300 rpm it was burning 21 gph.
I would really appreciate it if somebody anybody has any information on the Optimax and Ficht engines for this sort of horsepower.

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Joe

tsunami · 08 May 2001, 14:52

Cheers Alan,
look forward to hearing what figures you get with your new engine.
Yes, possibly a bad idea to fit the flow meter, I was thinking it might be a good idea to take it out and fit an hour meter instead!!!

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Joe

Alan · 09 May 2001, 00:06

And thats why I never fitted a fuel flow meter to our Johnson 150 VRO!! Didn't want to know how much it burned ... way too frightening!

All being well I will be able to shortly give you some feedback on a 150 Optimax as we are fitting one to replace our blown engine. Dealer literature says 40% more efficient but we'll see!

Alan

Mike Garside · 27 May 2002, 15:19

I searched for "flow meters" on RIB talk and this is the only thread I found. I'm keen to get one but have no knowledge nor info. Any leads gratefully received.

Cheers...

Alan · 27 May 2002, 15:48

Mike see PM ref. Floscan

Mike Garside · 27 May 2002, 16:48

Thanks, Alan.

David Hickman · 27 May 2002, 19:02

I have a Yamaha 200Hpdi on a 7.2m Rib with a Yamaha Fuel computer fitted on the console. Flat out its shows about 18 gph (46knots) Cruising at about 25knots it gives a reading of 7-8 gph. I have found that if anything it slightly over-reads.
Hope that this give you some help.

Phil · 27 May 2002, 20:52

I have been told that my Optimax will do 10gph at around 30kts;if the smart stuff on the dials works it is there orthere abouts;@35 /40kts have seen the figure16 displayed so changed the mode!

Garygee · 27 May 2002, 21:17

Sorry joe , thats why i am going for a diesel.

Estimates 5.5 GPH at 2600RPM (75% WOT) and 11GPH at WOT.
Oh forgot to add I will be paying 90P per gallon.

Thats when I get it

Only rubbing a bit of sea salt into the fuel bill wounds.

Regards
Gary

Mike C · 28 May 2002, 01:19

The Mercruiser 120hp is only suposed to use 2 - 2½ gallons per hour at cruising speeds, (25 knots ish). I'll let you know if it's true come mid July when my boat will be ready, (hopefully)

Boatless!

Alan · 28 May 2002, 07:55

Initial purchase cost is far lower for petrol, particularly on the bigger boats & what happens when the Govt is forced to give into the EU and levy full duty on diesel eh

!

Ok so I'd have a diesel too if I could afford it. Just trying to feel good about my position.

Having run both Optimax and HPDI (albeit only for a couple of weekends.) I can say that they are both a helluva lot more efficient than carbuerreted 2 strokes! Although my floscan has apparently given up the ghost when it was working on the 200HPDI I have now I was getting almost exactly 1 litre per knot until about 4/5's throttle when of course it all goes crazy. It is nice doing 51kts though even momentarily!

1 litre per mile is the rule of thumb I work too and then add +25% for safety in range calculations.

The Yam is certainly quieter than the Opti. At low speeds its almost like a 4 stroke!

Alan

Charles · 28 May 2002, 10:45

Now Alan.....don't get upset !

Jersey = 36P a litre!

Alan · 28 May 2002, 10:53

Even with cheap petrol you still don't seem to be able to shift that twin petrol engined gin palace of yours

Charles · 28 May 2002, 13:24

Now that's nasty.....people cannot afford it, grrrr!