Fuel consumption - merc. 502?
 

Does anyone know the fuel consumption on a merc 502 at cruise speed contra full speed...? The boat is a 25 feet scarab and everything runs great except for the fuel gauge... 2 times I've ended up getting towed to the marina by nice people... both times I was sure the fuel would be enough for the trip...

fuel
 

cant give you many details,but this is what i know.at a cruise at about 3500 rpm i burn 30 gals/hour +/-

30 GPH? You are talking twins right?

I have a 454 Mag in a '24 Superboat and at 3500 RPM I average about 10 GPH. With a 502 and your boat is probably a little heavier than mine I would guess maybe 15 gph.

fuel
 

that would be for a single 502 magnum,i always thought that this boat was a pig.baja 27'dry , it weighs 4400 lbs.i would also like to hear from others to see how much fuel they burn.it always seems that i am re-fueling .engine is stock except for a holly carb that i installed.

Hey Mark,

I would say that your gas consumption sound high. The MPI motors are probably more fuel efficient. My boat weighs about 3500lbs. It also has a 7' beam. I can cruise at 50 mph all day long on about 10 GPH.

Dave M.

for 502 efi

3500 rpm about 15-17 gph,
about 32-34 gph wide open

depends how its propped if heavy say wot=4600 you will be on hi side of that range if light wot=5000 on low side

Temp, humidity etc also makes a difference but thats a good ballpark

I run a 242 Formula w/ 502 cruise alot (long distance) and with hydromotive quad and RPM about 38 to 4 I burn 16 gallons a hour
If they smile when you pull up to fill up you must be doin it right:D
Rocket

I have a 502 MPI in my 28' AT. The boat wieghs about 5,000 lbs.
I would guess I burn 15-17 gph at 3500 rpm.

Maybe a little more in this photo:D

fuel
 

well,after the last couple of posts,now i know that i have been calculateing my fuel useage all wrong.

Mark,
I am glad I don't have your fuel bill!