Accuracy of Yamaha gauges

[Deep Blue]

On my 2003 Sailfish the Yamaha gauge displays the fuel level of either fuel tank, depending on which tank is selected. It's a vertical LED bar with segments.

I was at Catalina over the weekend and the aft tank showed 1/4 full yet there wasn't enough fuel to keep the engines running; the main tank had more than enough so I wasn't in any danger.

Exactly how accurate are these gauges?

 

[Ky Grady]

Do you have a fuel flow meter on your fuel line coming out of F/W separator? I re-set my gallons used each time after I fill my tank. What I put in and what I use per the meter are spot on, I was very surprised how accurate it was. The bars on the gage, to me, are more of a visual. I'll toggle through my mode buttons to get to my gallons used to really know what I have used out of a full tank and what I have left.

 

[DennisG01]

Mine are decently accurate - for a typical, float style gauge, anyways. You do get the slightly inconsistent (and normal) reading from F to E, but I don't ever recall being at a 1/4 on the gauge while actually being on E. When you fill up, you can confirm if you were really on E, or not. Otherwise, you could have a supply issue, such as a crack in the pickup tube, for example. But, let's confirm via how many gallons you put in, first.

Are the "bars" able to be calibrated? I'm not sure.

 

[seasick]

As Dennis mentioned, most likely the sender is bad or the pickup tube is broken. There is a less likely chance that there is an air leak in the fittings or fuel line that would lessen the fuel pressure (suction) to a point where there isn't enough lift to get the gas out of the tank. As mentioned, fill the tank and see how much gas it takes compared to it's capacity.
If you feel like doing a bit of work, and before you add gas, pull the sender and see if it is working correctly by lifting/dropping the float or the slide.

 

[DennisG01]

As Dennis mentioned, most likely the sender is bad or the pickup tube is broken. There is a less likely chance that there is an air leak in the fittings or fuel line that would lessen the fuel pressure (suction) to a point where there isn't enough lift to get the gas out of the tank. As mentioned, fill the tank and see how much gas it takes compared to it's capacity.
If you feel like doing a bit of work, and before you add gas, pull the sender and see if it is working correctly by lifting/dropping the float or the slide.

Note the part where he mentioned BEFORE... I bet you can figure out why...

 

[max366]

My fuel flow gauges are waaaay off. After perhaps 20 fill-ups, reset totalizer each time and then refill, I have observed they are consistently 18% off, reading a higher consumption than actual. The fuel level gauge is actually decent. So if I'm running on the main 130 gal tank, use 100 gal, (verified by the fill up mount) the fuel level gauge will read a little less than 25%, but the totalizer shows I used 118+ gal. I've done the adjustments that are possible but they are limited to +/-5%. At least it's wrong in the right direction!

 

[Legend]

I always reset the gallons used on mine after every fill up. I have found it pretty accurate - gives me a good idea of how much fuel I need when fueling so I know when to watch the nozzle to prevent overflows.

 

[Fishtales]

Same here. The resolution of the gage isn't super, but for the most part if you check them under the same conditions you can trust what is being displayed.

 

[glacierbaze]

My fuel flow gauges are waaaay off. After perhaps 20 fill-ups, reset totalizer each time and then refill, I have observed they are consistently 18% off, reading a higher consumption than actual. The fuel level gauge is actually decent. So if I'm running on the main 130 gal tank, use 100 gal, (verified by the fill up mount) the fuel level gauge will read a little less than 25%, but the totalizer shows I used 118+ gal. I've done the adjustments that are possible but they are limited to +/-5%. At least it's wrong in the right direction!

Not sure what gauge you are using, but the procedure sounds wrong. You say that you reset the totalizer BEFORE each fill up. I think that you calibrate most fuel gauges by it telling you how much you need, you fill up, and then you tell it how many gallons it actually took. You should get better accuracy with each fill, and after a few, be balls on.
I use my Lowrance for fuel management, and it gives me a calibrate option on every fill. It also gives me real-time gallons used, and real-time MPG, which is how I run my boat, for maximum mpg.

 

[max366]

Believe me, I have tried to recalibrate the gauges many times, especially after the first fill ups where I saw a large discrepancy. As I mentioned, Yamaha limits the amount of offset to about 5%, not sufficient for my situation. BTW I reset the totalizer after recording it's value into my fuel spreadsheet, then set it to zero once the tank is full. My many years using flow meters in nukes and chemical plants come in handy dealing with issue!

 

[glacierbaze]

Are you using an inline fuel transducer, or a feed directly from the engine?

 

[max366]

The Yamaha in-line transducer. 2004 F225s

 

[Deep Blue]

Do you have a fuel flow meter on your fuel line coming out of F/W separator? I re-set my gallons used each time after I fill my tank. What I put in and what I use per the meter are spot on, I was very surprised how accurate it was. The bars on the gage, to me, are more of a visual. I'll toggle through my mode buttons to get to my gallons used to really know what I have used out of a full tank and what I have left.

I don't believe so, this sounds like a great idea. My blue Yamaha canister filter is under the aft cockpit seat about 1-2 feet away from the fuel valves - can you recommend a brand, do I need one or two? Thanks.

 

[Deep Blue]

Mine are decently accurate - for a typical, float style gauge, anyways. You do get the slightly inconsistent (and normal) reading from F to E, but I don't ever recall being at a 1/4 on the gauge while actually being on E. When you fill up, you can confirm if you were really on E, or not. Otherwise, you could have a supply issue, such as a crack in the pickup tube, for example. But, let's confirm via how many gallons you put in, first.

Are the "bars" able to be calibrated? I'm not sure.

When we filled up a couple of weeks before the tanks were full and the Yamaha gauge showed full for both. Waiting for fuel prices to drop, everything is over $4/gal...

 

[Ky Grady]

I don't believe so, this sounds like a great idea. My blue Yamaha canister filter is under the aft cockpit seat about 1-2 feet away from the fuel valves - can you recommend a brand, do I need one or two? Thanks.

Mine is on the outlet side of the separator, but I only have a single.
Part number is 6Y5-85752-02-00, Fuel Flow sensor.

If you only have a single feed line from the filter, you'll only need one. Not sure how your fuel lines are setup.

 

[glacierbaze]

Choose your fuel transducer according to how you want to see the readout, on your Yamaha gauge, or on your GPS. Mine is networked to my Lowrance.
If you have twin engines, you definitely want two transducers, or you’ll either have to flip back-and-forth, or only see an average. I would want to know if one engine started sucking fuel more than the other.

 

[Deep Blue]

Mine is on the outlet side of the separator, but I only have a single.
Part number is 6Y5-85752-02-00, Fuel Flow sensor.

If you only have a single feed line from the filter, you'll only need one. Not sure how your fuel lines are setup.

Ky Grady,
Found them, I didn't realize they were a Yamaha part. Ok, there's an electrical connector on the part, where does that connect? As I have a 2003 I don't have the benefit of NMEA to the engines.