Merc 90 fuel consumption Q

[CharlieZulu]

20-yr old Merc tower of power 90 hp, but new to me this season.

On a 30 min cruise with only occaisional WOT I use up about 10 litres of gas (about 2 1/2 gal)

is this considered normal?

 

[emckelvy]

Re: Merc 90 fuel consumption Q

That motor will burn approx 10 GPH at Wide Open Throttle, so I'd think that 2.5G in 30 minutes of cruising isn't unreasonable.

HTH...........ed

 

[hl]

Re: Merc 90 fuel consumption Q

That is good considering the boat your pushing is fairly heavey.

 

[Rscardina]

Re: Merc 90 fuel consumption Q

basic rule of thumb is 1 gal per hour for every 10 HP at full throttle

.. example= 90 hp engine 1 gal x 9 = 9 gallons per hour at full throtle

this is just a rule of thumb and may change based on conditions, wind, chop etc..

sounds pretty on to me...

 

[emckelvy]

Re: Merc 90 fuel consumption Q

Actually, the HP/10 rule is good for crankshaft-rated motors. Propshaft ratings will use more fuel than that because, for example, a 90hp propshaft-rated motor is at least 100hp at the crank.

BTW, that 3-cyl is not a Tower of Power, that name is reserved for the World Famous E.C. Kiekhaefer-designed Inline Sixes!

Maybe you could call your 3-cyl a "Mini-Stack", it's actually a pretty good motor and at least worthy of that moniker!!!

 

[CharlieZulu]

Re: Merc 90 fuel consumption Q

Thanks, guys... and how can you tell my boat is heavy?

 

[Mi duckdown]

Re: Merc 90 fuel consumption Q

Want to save gas? Get it on plain at full throttle, then back off on the throttle to keep it on plain. You can probably run 3/4 throttle, once on plain.