Fuel flow rate for Yamaha 250

[Killertraylor]

Well, I finally had a fuel flow meter hooked up to my 23 foot Northriver. People asked me to post the data after I got it hooked up.

I've always been nervous about going TUNA! fishing even though I've got a 93 gallon fuel tank. I've heard several contradictory stories about my fuel burn rate with my 250 Yamaha Saltwater series. I even considered trading down to a Honda 4 stroke last summer until several of the smarter Salty Dogs talked me out of it. Turns out I'm glad they did.

I got a really good fuel flow meter - a FLOSCAN. They are about $325, but they're aircraft quality and it really seems to work well for what I wanted. It has a needle/dial guage similar to your spedometer in your car and the needle measures your burn rate at that given second. There is a small digital "odometer" at the bottom that keeps track of the fuel burned that trip in gallons. There are two toggle switches - one to turn the unit on and the other to reset the "odometer" when you fill the boat up again.

Here's the data for my 250 tested while crabbing on the Columbia. At 3700 rpm, which is my ordinary cruising speed (31 mph)I'm using 8.2 gallons per hour - not too shabby! At idle (700 rpm) I only use 1.2 gallons per hour and at full throttle (5500 rpm - 52-56 mph) it used 14.8 gallons per hour. That gives me plenty of range - I just need to go to a gas station now that isn't very busy so I can let the toungue of the trailer all the way down and make sure my tank gets all the way full - once I do that one time, I should be able to know precisely how much gas to add each trip to keep it full. Pretty Cool!

For those interested, Northriver only charged $190 to install it (I bought the unit at West Marine) which included mounting the sensor and plumbing it to my fuel line, running the wires and mounting the toggle switches and cutting a hole in the dash to mount the guage. Not a bad deal at all.

[Miss B Haven]

KT- Unless you plan on dropping the trailer every time you fuel I'm not sure why you should do that. :shrug:
What you really need to do is fill it normally and then run it dry so you know what your true USEABLE fuel is. Not an easy thing to set up and do. You have to carry a backup gas can and make sure you are in a situation where a) it won't hurt to have the motor quit and b) the spare can will get you home or to the fuel dock.
It's a lot easier if you have more than one tank and you can run each one dry to do the check.

THis is gettting pretty anal about it though since you always want to have 1/3 in reserve. If that 1/3 reserve is off by a couple gallons it's proabably not the end of the world.

[Killertraylor]

I hear you, Mel - however, I think sometimes the tank gets all the way full without dropping the trailer tongue, but it will definately get all the way full if I lower the bow - the vent is in the back of the tank right where the fill hose goes in so I know it will always fill up with the bow tilted down. You're right though, it would be nice to compare the "Odometer" on the meter to the actual useable fuel - I don't plan to ever cut it that close though. Thanks for the idea.

[shorthair]

much easier way to get level is just put a couple of blocks under your tires to park on you wont need much to get leveland its way faster than disconnecting.

[Thumper]

Hmmmm.....Your data indicates a range of 352 miles at 31 mph vs. 346 miles at 55 mph. Is that likely?

[Flatfish]

KT,

we have the same motor. Just wondering what your boat weighs.

Have not had the prop on yet( will about hang the pump up around smelt time), and am wondering how fast this thing is gonna go. Fast enough I guess. If I need more speed, they do make a 300 hp Yammie.....

Thanks.

Mark and the watery eyed dog.

[darth baiter]

Is there a calibration process for flow meters? The flow rates you're getting look almost too good when compared to the flow rates shown on the performance tests for Yamahas on their website. The wide open throttle rates they show for big 2 stokes (including HPDI) are nearly double the rates that your flow meter registered. Even the big 4 strokes couldnt come close to 14 gph at WOT. You've got a good one if you're getting that kind of gas mileage with that size boat.

[Killertraylor]

Maybe I need to check that Wide open throttle number again? I posted it off of memory - I'm postive about the flow rate at 3700 because I ran the boat there for a long time while getting to our crabbing spot, but I might not have the 5500 RPM number correct - I just ran it up there briefly to check it out. Yes - the meters can be calibrated - the guy that installed it at North River calibrated it for me - he seemed to know what he was doing so I hope he did it right.

Mark - I'm not sure what my boat weighs, but on the trailer full of gas it's 5400 lbs. I'd guess the tandem axel trailer weighs about 1500 lbs - does that seem right? My best guess is that boat and motors weigh about 3900 lbs when its full of gas.

[ 11-23-2003, 10:12 AM: Message edited by: Killertraylor ]