90HP Mercury pushing 24' pontoon

[TDiddy51]

Just bought a 24' 2010 Tahoe tritoon and have a 90HP Merc w/stock prop. Boat was previously on a smaller lake. I moor on the Belle River in Marine City Michigan about 1/2 mile off the St Clair River with its 8 knot current. If I go north to St Clair or Port Huron, the boat is sucking up the fuel. I do plan to "skin" the underside in the offseason. Any other financially feasible suggestions to increase speed/fuel consumption? I know it ain't a speedboat, I just want a little more flexibility on destinations.

 

[jimmbo]

Stock Prop? Mercury does not ship Engines above 25hp with Props. What do you consider "sucking up the Fuel"? 9 gallons/hr would be an Acceptable rate of Consumption

 

[captmello]

I installed a larger fuel tank in mine to increase range and refueling frequency.

 

[ahicks]

Stock Prop? Mercury does not ship Engines above 25hp with Props. What do you consider "sucking up the Fuel"? 9 gallons/hr would be an Acceptable rate of Consumption

Yup, need to know what's on there now, and how fast you can turn it (max rpm). THEN we might be able to help. Skinning would likely be a good option, as well as keeping the boat as light as you can.

 

[jlh3rd]

this is what I get with my 24', twin 25" tubes, 2021 115 hp CT motor.
I don't think there's any tweaking you or I could do to make mpg go up...Ive done all I know offhand...which is really nothing except propping and trimming....Underskinning maybe down the road.....
I didn't know that people underskinned a tritoon.....
figures were attained using gps speedometer and smartcraft tach with fuel burn...

 

[jlh3rd]

these stats are current as of today with my 4 blade, 14x14....fyi to show as a comparison. .....
you can see it's not a big differences in mpg.......
I can't hit my 6000 rpm with the 4 blade, but there is a good speed differential compared to the 3 blade......but mpg is still close....more speed, more gas.....

and the prop pictured is the 3 blade, 16x12 and what happens when it meets a rock at 1500 rpm......

 

[jimmbo]

Any other financially feasible suggestions to increase speed/fuel consumption?

First time I remember ever seeing someone wanting increase Fuel Consumption... Other than Oil Company Executives

 

[jlh3rd]

what's wrong with oil Co. executives wanting their products to be used? ...my grocery store wants me to buy groceries. Parts departments want me to buy parts. Home Depot, Lowes wants me to build stuff . ...
Real estate Co's want to sell real estate.....Isn't that why "some" people buy multiple millions of dollars of beachfront properties....even though these same people tell us everythin's gonna be underwater in 8 years?....
I love capitalism and rich people......
drill baby drill....

 

[ahicks]

FYI, the 4 blade is not about increased speed as a rule. It's about increased bottom end torque (yanking a tube out of the water for instance) and low speed maneuverability (like when docking, loading and unloading). They're also pretty well known for holding the boat on plane at lower hull speeds.

The piece regarding holding a boat on plane at lower speeds may be of interest to you? I would think that the boat would be pretty efficient at the lowest speed it could hold the boat on a clean plane.....

If you want to go fast, you want less blade area. Clearly the 4 blade will be counter productive here.

Last, unless your emphasis is on tubing and the like, and keeping in mind it's a 4 stoke, I've found a 5500 rpm target speed works quite a bit better than the manf's red line. Engine doesn't sound as busy, and it can actually be worth a mile or 2 an hour....

 

[jimmbo]

what's wrong with oil Co. executives wanting their products to be used? ...my grocery store wants me to buy groceries. Parts departments want me to buy parts. Home Depot, Lowes wants me to build stuff . ...
Real estate Co's want to sell real estate.....Isn't that why "some" people buy multiple millions of dollars of beachfront properties....even though these same people tell us everythin's gonna be underwater in 8 years?....
I love capitalism and rich people......
drill baby drill....

Let me rephrase that. Change 'Oil Company Executives' to 'Petroleum Robber Barons'

I love a Healthy Percentage of Socialism. Many things, like Energy, Communications, Healthcare are far too Important to be left in the hands of Capitalists. I would like a to see a 50-50 split, that way each side can keep the other in line.

 

[Scott Danforth]

If you want speed, buy a planing hull. Pontoons take lots of power to go fast

If you want fuel economy, just putt along or get oars or a sail

A 4-stroke OB will burn about 0.45# of fuel per HP per hour. So 0.45 x 100hp (crank, not the 90hp at prop) x 1 hour will be in the neighborhood of 45# of fuel, or 6.6 gallons (6.82#/gallon)

A 2-stroke OB will burn about 0.5# of fuel per HP per hour (0.5 x 100hp / 6.82 ) or 7.4 gallons

A 90hp motor on your boat is only a mph or two faster than a 50hp, yet burns almost double the fuel

 

[jlh3rd]

yeah...I know you do......I see every day the results in other countries that have to follow your guidelines....
.....funny that I never see their carriers and their manpower at work around the world when natural disasters strike....

Let me rephrase that. Change 'Oil Company Executives' to 'Petroleum Robber Barons'

I love a Healthy Percentage of Socialism. Many things, like Energy, Communications, Healthcare are far too Important to be left in the hands of Capitalists. I would like a to see a 50-50 split, that way each side can keep the other in line.

oh yeah, sure...50/50....so rational, so righteous ..right....didn't something happen in germany back in the day that was supposed to be " for the people"...
Ever hear of the fairy tail, the golden goose.....as in killing...i'm watching that happen....I'll not shut up...
idiot people spouting ignorant stuff after benefiting from the hard work and entrepreneurship endevors of previous generations....
yeah....I know you....
why are you even on here?....you want all this to go away....
hypocrisy.....

 

[jlh3rd]

sorry tdiddy51...just trying to post stats fyi...and anyone else...

 

[Scott Danforth]

@jlh3rd let's keep it civil