Best cruise on a Merc 100

[strokersquid]

I have a 100 HP Merc on a 17 ft Arima Sea Ranger. If my map is coorect it took about 18 gallons of gas to go 40 miles at 3600 rpm in not so bad conditions. This sounds like terrible milage for such a light boat that is made for economy. Is there a problem here ? It was checked by a mechanic prior to purchase.

 

[SparkieBoat]

Re: Best cruise on a Merc 100

thats about 2 MPG...about right. you need to experiment with different RPMs, you may find it does 0.5 MPG better at around 4300-4800 range, every boat will be different..just so you know many boats average 1 MPG or worse. the motor you have was not known for great MPG.

 

[strokersquid]

Re: Best cruise on a Merc 100

Did any of the older carb'ed 2st get good economy, or is it only 4st or 2st DI of recent years that do well ?

 

[SparkieBoat]

Re: Best cruise on a Merc 100

you should do some google searching on Outboard MPG test...even DI or EFI or 4 strokes do not get what I would call good economy. when you weight out the extra cost of a newer motor and the way higher cost of maintenance, you really lose out if you are looking for economy because you will only reduce your fuel bill slightly. most carbbed motors from the late 80s and early 90s did about as good as you could get on fuel mileage. what year is your motor? again trying different cruising speeds could make a big difference...also make sure your motor is mounted at the proper height and is properly propped, these can make a big difference also.

 

[strokersquid]

Re: Best cruise on a Merc 100

motor is a 1993. Sparkie said that model "was not known for great MPG" so I thought possibly there were better outboards of the era for economy. New motors would cost more than the boat is worth.

 

[SparkieBoat]

Re: Best cruise on a Merc 100

I did not mean your model specifically, most outboards are not known for fuel economy, I meant it in a more general sense. Generally speaking you cannot expect what you would call good MPG, specially when you compare a boat with a car. I am not sure exactly why it takes so much more energy to move a boat across water than a car across land but it does. some of the newer 2 stroke carbbed motors do get slightly better MPG, I know OMC came out with Optical Ignition System 60 degree motors in the mid 1990s that did see an improvement in MPG although it was slight.

 

[strokersquid]

Re: Best cruise on a Merc 100

looks like there was EFI too, but only on the larger engines.

 

[strokersquid]

Re: Best cruise on a Merc 100

any way to monitor fuel use on the fly ?

 

[SparkieBoat]

Re: Best cruise on a Merc 100

seems like there are some inline monitors that measure Gallons Per Hour (GPH) do a goggle search