Approx How Much Fuel

ok guys i have a 1977 merc 50 hp 500 motor on a 14 ft larson lapline boat, approx how much fuel will it burn an hr most of the time i will only be running like maybe 3-7 miles then running electric trolling motor. this boat and motor is new to me im not a wide open runner say maybe 3/4 throttle to gets there and back, im just curious as i have a 6 gal portable fuel tank, i also may pull some rapalas behind boat sometimes as it has a happy troller plate on it MANY THANKS

Re: Approx How Much Fuel

It would burn about 5 gallons per hour at Wide Open Throttle (WOT)

Re: Approx How Much Fuel

As said around 5 gallons per hour at WOT. Significantly less at cruising speeds. Take more gas than you need till you get to know how much you will be using. Then as a rule of thumb allow 1 third of your gas for the trip to where you are going, 1 third to get back and one third for the unexpected.

Re: Approx How Much Fuel

Ok thank you this will help, i also have a 14 ft aluminum boat with a scott attwater 10 hp bail-o-matic and it only uses like 3 gal all day going to and from and trolling so was just needing to know what this bigger boat would use

Re: Approx How Much Fuel

frwhlr38 said:

it only uses like 3 gal all day going to and from and trolling

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If only my motor did the same thing !!!!

Re: Approx How Much Fuel

Merc has what is called a "back drag" function. When you get ready to start your run to your "honey hole" push the throttle all the way on. Wait till the boat's speed stabilizes, and then cut your throttle to your cruise speed.

What happens when you do that, is that at full throttle, your ignition timing is fully advanced and your carb throats are wide open. But when you back off your ignition stays fully advanced for awhile but your butterflies start closing immediately. Saves disproportional amounts of gas for the slight reduction in performance.

Pop the cowl and observe the throttle linkage both at the carbs and linkage going up under the flywheel. Move the throttle and watch the linkage and you will see what I mean, and also can observe at what throttle setting, the spark starts backing off.

On the ScottAtwater, that is what daddy bought for us when I was young; he bought it specifically for the Bail-a-matic. We'd rent the boats and the 10 hp was light enough to carry each time we rented a boat. It wasn't much for the load it had to push, but it was better than oars. Grin

Mark

Re: Approx How Much Fuel

oh yes texas i love the bail-o-matic not a speed deamon but i aint either and runs like a champ, i will try that on the merc as i wont have it in the water till spring, but cant wait i stoped fishing when i was in 20s and now im retired im back into it and OHHHHH man i love it thats why i dont need a speed deamon just enough to gets me there and back and have fun doing it