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Author Topic:   Fuel Consumption 90-HP Four-strokes: Mercury vs Suzuki
imko posted 07-31-2004 02:28 PM ET (US)   Profile for imko   Send Email to imko  
Boat 1: Montauk 170 with Mercury 90 4-stroke 2003
Prop: Trophy Plus 13,75 x 19
Crusing at 3500-4000 rpm (1 person)
Fuel consumption: 37 litres or 10.3 gallon

Boat 2: Montauk 170 with Suzuki 90 4-stroke 2001
Prop: aluminum 14 x 19
Cruising at (same speed) 4000-4500 RPM (2 person)
Fuel consumption: 23 ltr or 6.4 gallons

The Suzuki has a better hole shot and the same top speed. Also it's a much smoother engine and has more torque compared to the Mercury.

The new Mercury 90 4-stroke (2005) has fuel injection (same as the 90 Suzuki). Is this new engine the same displacement (1600cc engine) or is it a 115 (1740cc) engine?

Is the fuel comsumption dropping with this new engine?



jimh posted 07-31-2004 07:19 PM ET (US)     Profile for jimh  Send Email to jimh     
[Administrative post]
jimh posted 07-31-2004 08:45 PM ET (US)     Profile for jimh  Send Email to jimh     
How reliable are those fuel consumption measurements?

It is hard to believe that two four-stroke engines of identical horsepower operating identical boats at identical speeds could exhibit such a range of fuel consumption. The one running at 15-percent more throttle (4000 vs 3500) produces fuel consumption that is 38-percent lower! And it has twice as many passengers!

This is an amazing outcome. Even compared to conventional high-emission two-strokes, outboard manufacturers only claim a 40-percent improvement. Here is a 40-percent difference just between brands of modern four-stroke engines. If these astonishing figures are true, the Suzuki marketing people must be idiots not to publish these numbers in all of their advertisements.

I can say this, if Mercury had this miracle motor, you'd have heard about it already!

erik selis posted 08-01-2004 03:50 AM ET (US)     Profile for erik selis  Send Email to erik selis     

I'm assuming that you are comparing the fuel consumption of the 2 boats under the same circumstances. Meaning running the same distance on the same waters at the same time. No?
Only in these conditions can you compare the real fuel consumption IMO.

When I am boating in the "Oude Maas" or "Het Spui" in Holland I use about 40% more fuel running against the strong current compared to running with the current. I therefore always check the tide tables and calculate the best time to run these waters.

I can imagine that there is a slight difference between the 90-hp 4-stroke (carb) Mercury and the fuel injected 90-hp 4-stroke Suzuki but your results are, to say the least, surprising.

I'm just curious here, but what happened to the Mercury motor on the second 170 Montauk? Is it a Dutch boat? Was the Mercury exchanged for the Suzuki and if so where was is done? I haven't heard of any Dutch 170's that have been "dealer delivered" with any other motor than a Mercury.

I also saw that the Suzuki motor was a 2001 model. Is the 170 Montauk with this motor also a 2001 model because this would mean that it is the older Montauk model?


imko posted 08-01-2004 06:53 AM ET (US)     Profile for imko  Send Email to imko     
Sorry Erik, youre right: Boat 2 is a 17 Montauk and has
less weight comparing the Montauk 170.
But the difference in fuel comsumption is a lot! Boat 2 is
a boat from Germany. The circumstances are the same on this trip. (namelijk de waddenzee,Erik)
I try another prop this week (laser II 13,25 x 20)
The Trophy plus prop. is a four-blade and the laser II is a tree blade prop. The Trophy plus is (i think)to heavy prop.for this engine.
My cousin has a Wahoo 1750 offshore with also a 90 Suzuki
4-stroke. His fuel consumption is also about 30% less than the Mercury 90 4-stroke.
I hope the new four-stroke 90 EFI from mercury is the same as the 115 with the same weight and a better fuel and consumption!!
Next week i compare the fuel consumption with this new prop.

Regards (groeten),


imko posted 08-14-2004 01:28 PM ET (US)     Profile for imko  Send Email to imko     
New results with the Laser II prop.

The fuel comsumption dropped a little comparing the 4 bladed Trophy plus and the laser II (13,25 x 20)
The engine is much smoother running with this prop, and also the fuel consumption is better.

Boat 1: Montauk 170 with Laser II,1 person and 1 tank (6 gallon) of fuel.

Boat 2: Wahoo offshore 1750 90 suzuki 4-stroke (weight boat ± 450 kg)) with
1 person and a and 20 gallons off fuel.

Boat 1: max rpm 5700, top speed 44,1 mph. Fuel comsumption
13,0 ltr same trip as Wahoo.

Boat 2: max rpm 5500 with alum.prop 14 x 23, top speed 42,2 mph. Fuel consumption this trip 10,6 ltr.

I think that the trophy prop. is to heavy for this engine,
and thats why the fuel consumption dropped with the laser II.
This prop is also better than my first Vengeance prop (13,25 x 18)It has a better mid-range and the top speed is
higher. The hole shot with te Vengeance prop is better, buth the max rpm. (6200) is to much!!!

erik selis posted 08-14-2004 01:40 PM ET (US)     Profile for erik selis  Send Email to erik selis     

It looks like the fuel consumption dropped a lot with the laser II prop. I think that both engines will give about the same fuel consumption if used on the same boat. Don't forget that the Wahoo is still a much lighter boat than the 170 Montauk even with the extra fuel it carried.

Thanks for the information. I think many people here with the 90-hp 4-stroke Mercury will appreciate it.



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