85 hp force fuel consumption

[stobbs]

I have a 1986 85 force on a 16 foot boat that uses about 7 gallons of gas in 2 hours just putting around in the lake. The boat runs great but sucks the gas. Is this a normal for this engine? Any help would be great. Thanks.

 

[MWBROWN]

Re: 85 hp force fuel consumption

I have a 1984, 85 HP on a 16 ft Fish and ski by Balyliner.
I get about 4 MPG running on plane at about 5000RPM.
Just putting around it seems to use more, since it is pushing more water. The last long run I made I used 14 Gal in 56 miles. If I run wide open, it drops off.

Hope this helps you.

Mike

 

[steelespike]

Re: 85 hp force fuel consumption

The Force has a reputation for using fuel.
What is just putting, trolling or on plane.Rule of thumb
says about 8.5 gallons at WOT.Careful adjustment of the idle mixture screws idling in gear might result in a little better idling fuel use.If the fuel pump diaphram is leaking it would cause excessive fuel use.Would usually make it smokey as well.
To give you an idea where your at an Etec uses almost 2 GPH at 2,000 rpm but only 3/4 GPH at 1,500.So you could be running just fast enough to be in the higher use range.

 

[Matthew A.]

Re: 85 hp force fuel consumption

My 17 foot Bayliner Capri loaded with two people, 7 gallon bait tank, 300 to 400 pounds of gear including rods, reels, tackle, cooler, battery, anchor, chain, 60 lb. tool chest, ect ect. and up to 40 gallons of fuel, heading into light 2 to 3 foot swell and less then 1 foot seas gets around 23 miles [or 2.8 mpg.]on 8 gallons of fuel at an average speed of 15 knots. This includes 5 miles of trolling @ 5 to 6 knots. If running on flat calm seas with little to no wind at a cruise speed of 18 to 23 knots such as looking for kelp paddies the motor gets around 5.6 mpg. As an average for this motor, 2.5 to 3.0 is about right for the conditions the motor is run. Having to cruise at speeds less then planing or when cruising in rough seas [3 foot wind chop or higher @ less then 7 second intervals] and the mileage drops big time. As low as 3/4 mpg or worse.
The best mileage we've ever gotten was heading home downhill on 10 foot swells. 3 adults w/ all the gear as above. Heads kept low below wind screen. 80 miles @ 21 knots on 12.5 gallons of fuel. Or 6.4 mpg.

 

[strawberry mivi]

Re: 85 hp force fuel consumption

Got to agree with the first post.
Constumption, although never measured seemed high.
2 hours of donut towing saw me running on fumes (85Hp, 10 litres of fuel)

 

[steelespike]

Re: 85 hp force fuel consumption

2 hrs.10 liters= a little over 2 1/2 US gallons Thats only 1 1/4 GPH.Seems low to me.
As I said the GPH rule of thumb for any outboard is 10% of the HP. at WOT. 8.5 GPH for 85 hp.
And a small change in RPM can be a big change in GPH.

 

[javsam]

Re: 85 hp force fuel consumption

yes based on what you have so far, that seems about right to me.for best fuel use run throttle at about 3/4
position.:%