twin engine more gas than other

[woodtic]

I have two 35hp 78' evinrude one of my motors uses more fuel than the other on average 16 mile trip it will consume two to three gallons more than the other which is not a big deal but could it be that out of tune any tips on this??

 

[d.boat]

Re: twin engine more gas than other

I have two 35hp 78' evinrude one of my motors uses more fuel than the other on average 16 mile trip it will consume two to three gallons more than the other which is not a big deal but could it be that out of tune any tips on this??

are they running at the exact same rpm's on the exact same boat, same load, prop, set up etc?

What speed are you going - in other words how long does it take to go that 16 miles? What are the amounts of fuel used? The reason I ask is because those two engines shouldn't burn more than 3 gallons per hour each at cruise speed (as opposed to wide open), which makes 2-3 gallons over 16 miles quite a large difference assuming it takes a couple hours or less.

 

[woodtic]

Re: twin engine more gas than other

they are both on one boat 18ft holiday props are 10 1/2 x 11 I would be lucky to be doing 14 to 16 mph cruising speed 3/4 throttle wot 22 mph wot rpms 6500 if it is accurate only one tac working it could be running harder than other motor load 500 to 600 lbs. more pitch on prop would help speed no gas leaks both seems to be running good but always seems to burn a little more gas sense I got it

 

[Incorrigible]

Re: twin engine more gas than other

Would recommend repairing the second tach so that you can compare the two accurately. If that's not feasible, check the engine speed on the engine with the working tach, then switch over the wiring to the second engine and get a reading. That's acctually a lot of different in fuel comsumption. Start there...

 

[d.boat]

Re: twin engine more gas than other

they are both on one boat 18ft holiday props are 10 1/2 x 11 I would be lucky to be doing 14 to 16 mph cruising speed 3/4 throttle wot 22 mph wot rpms 6500 if it is accurate only one tac working it could be running harder than other motor load 500 to 600 lbs. more pitch on prop would help speed no gas leaks both seems to be running good but always seems to burn a little more gas sense I got it

So, how much gas per hour are they actually burning (each) when you're going 14-16 mph? Like I said above, if that's 3/4 throttle, they shouldn't be burning any more than about 3 gallons each in that 1 hour, 16 mile run, which makes the difference you're describing a very large difference, like 2X.

 

[woodtic]

Re: twin engine more gas than other

I hear what your saying that is a big difference I top off both tanks 6gal switched tanks for trolling on return switched back one tank empty other still had close to 2 gal. just checked it out. I have notice this before but not to the point of a empty tank this was longest run I went on this boat. I didn't pay any attention of time for distination had to be close to 30 to 40 min. in and out of wot for short time and bact to 3/4 you are right it dont add up to 3 gal. per hour. really looks like I need a working tac for other motor maybe I'am working one harder than other. I did change plugs today in the motor that seems to use the most gas it deffinitely needed it I do not have a speed indicator I'am only going by a friend that had a hand held GPS that went with one time