hours/gallons conversion--help

[motownmasher]

just got my new rig. 1652 G3 with a 60/40 yamaha jet. wondering what an average is for gph. i realize with a jet this would be a different conversion than a prop, however i just want to be close as far as break-in. any help would be much appreciated. wouldn't have to be the identical motor, just some numbers what your rigs will do as far as gallons per hour. didn't wanna shell out for the hourmeter.

[delcecchi]

just got my new rig. 1652 G3 with a 60/40 yamaha jet. wondering what an average is for gph. i realize with a jet this would be a different conversion than a prop, however i just want to be close as far as break-in. any help would be much appreciated. wouldn't have to be the identical motor, just some numbers what your rigs will do as far as gallons per hour. didn't wanna shell out for the hourmeter.

An old rule of thumb for two strokes was 1 gallon per hour per 10 HP. So a 60hp would use 6 gallons per hour. Four strokes and new technology two strokes use less.

[motownmasher]

less than 6 gallons an hour.... if this is the case it will take me a couple years to complete break-in. which they say is 10hr. i'd be guessing it closer to 2gph, but as stated. it is a jet which are renown for being gas guzzlers.

[bwa]

if it is a 2 stroke 60 horse the 6 gal/hr estimate is correct, at wide open throttle. because it is a jet doesn't mean it will burn fuel at a faster rate, just means you will travel a shorter distace & at a slower speed.

[Brad B]

less than 6 gallons an hour.... if this is the case it will take me a couple years to complete break-in. which they say is 10hr. i'd be guessing it closer to 2gph, but as stated. it is a jet which are renown for being gas guzzlers.

based on your post I am guessing you are trying to figure out how long the 10 hour break in will take you based on the number of gallons you run through it. here is my advice. take this season and run the motor at no more than half throttle on a continuous basis. you can bump it up to 3/4 throttle but don't do this for more than 5 minutes at a time. once you do this then you could open it fully but there again do it for short time periods (5 minutes). the whole thing with the break in period is you are just letting everything in the engine seat properly. if you put it to full throttle right away with out doing the break in you risk the chance of blow by on your pistons and then you will get gas mixing with the oil. if you would like to get the actual number of hours on the motor you can take it a yamaha dealer and they can put it on the computer and check the number of hours on the motor. this same scan will also tell if any alarms went off and what caused them. I am going to have my yamaha checked for hours sometime this summer. I am going to have it done at A1 in Annandale. by the way I have a 40HP prop drive. expect to get speeds of around 25MPH with the jet. it may be a 60HP power head but your output at the jet will be around that of a 40HP that is why I say expect speeds of around 25MPH.

[delcecchi]

The 6 gallons per hour, for a conventional 2stroke, is at wot. If you back off, you reduce gas consumption by about the square of the speed. So if you are going at 3/4 as fast as WOT then you are using a little more than half as much gas per hour. (3/4 squared is 9/16 or 56%)

Yes 10 hours of running on a boat is a surprisingly long time. Just got a new motor last spring and was surprised how long it took to get the hours on, just normally fishing.

[motownmasher]

wow!! this is gonna take forever. i almost hate to even ask, but this is a 2012 4 stroke. what would your guesses be as far as the newer 4 strokes. i guess best bet would be to check my watch and run it for 30min. thanks to all for your help.

[Brad B]

like I said if you want to know the exact hours spend $60 and have a yamaha dealer hook it up to a computer and run the scan on it. by the way the motor I have is the 2011 40HP 4stroke prop drive. just to give you a idea I filled my 6 gallon tank and ran all the lakes of the sauk river chain of lakes and used less than a half a tank round trip(about 10 to 15 miles from one end to the other and back). you will find that the Yamahas use very little fuel. of course I don't run mine wide open all the time. so that might explain the gas savings also. over all they are great motors and hold a good resale value if you ever sell it.