Yamaha 2021-2023 Low Fuel Alarm, Reduced Fuel Tank capacity?

[svhooo]

I will do a top off and report back. I tend to fill every trip so rarely get to absolutely empty. I do this to try to avoid the alarm

If you're measuring to the time the alarm comes on, then I predict about 30 miles.

[Wild Thing]

I know it alarms with about 38ish litres left in theroy but then with rencent discoveries regarding overal tank capacity being lower takes that back to maybe 28 ish useable. And yamaha had the nerve to say they done this to stop silly people running out of fuel mid ocean. I call b.s

[K447]

… alarms … overall tank capacity … maybe 28 ish useable.
And yamaha had the nerve to say …

Most of us have assumed the Fuel Tank Capacity number posted in the service manual or on the manufacturer web site was sufficiently correct.
We have now learned that the printed ‘spec’ for fuel tank capacity is not trustworthy. Nor sufficiently useful.

What the enthusiast community should be doing is actually measuring the fuel tank.
And characterizing the fuel gauge readings. And the fuel warning level(s)

This is what Mr. GP1800 has done for his 2023 FX SVHO
And for his 2017 GP1800 SVHO

This is what other members should also do with their own watercraft.
Re-doing the same tests with other examples of the ‘same fuel tank’ should confirm the numbers. If the numbers differ significantly then that should be highlighted and perhaps further investigated.

We also generally assume that a manufactured product would be consistent between dash readings and actual fuel levels inside the tank, across all the HIN of the same model. This assumption should be tested.

The important numbers include;
Starting from the fuel level where the fuel pump in a non-moving hull on land (a ‘level hull’ condition) begins drawing air

How much fuel can be added to the ‘empty’ fuel tank to fill it ‘to the brim’
This is effectively the headline ‘Fuel Tank Capacity’ number*

How much fuel is added when the Low Fuel warning ceases
For each increment of the fuel gauge dash reading, how much fuel has been added to the tank
When the dash gauge first touches ‘Full’ how much fuel has been added
How much additional fuel can be added beyond when the dash first shows ‘Full’

Using the on-board fuel pump to slowly empty the fuel tank, make note of the amount of fuel removed for each change in dash ‘bars’ reading, and how much fuel has been removed when the Low Fuel warning first occurs. From there, how much more fuel can be removed until the fuel pump again draws air

Bonus points if for each increment of fuel added the level sender ohms number is also measured and noted. The ohms info can separate differing sender values from differing dash display of those ohm values, for a given amount of actual fuel in the tank #

We should do this not just for the 2021 onwards Yamaha models with the new, and apparently smaller, fuel tank.
The same measurements should be done for the prior Yamaha fuel tank part number (in whatever models that tank was used in).

This is the electrical rig I made to manually control the Yamaha fuel pump.

https://www.greenhulk.net/forum/personal-watercraft-performance-skis/yamaha-pwc-performance/yamaha-pwc-performance-4-stroke/259816-manual-fuel-pump-control

This is the metal fitting to mate with the Yamaha factory fuel hose from the tank
https://www.greenhulk.net/forum/pers...=1#post2993344

We should also measure the other PWC brands for the same fuel tank capacity and dash reading information.


* What we will then have is fairly accurate information, after doing all the measuring.
Knowing how much actual fuel is in the tank at each incremental ‘level’ will inform the rider as to how far they dare ride.

Most riders never ride until the engine stops due to fuel starvation (for obvious reasons). And if they do, there may not be opportunity to accurately measure how much fuel it would take to refill the tank completely from ‘just ran out’. Doing these fuel quantity measurements on land should allow the measurements to be consistent.

Several owners with the same tank ‘model’ should measure very similar amounts of actual fuel for each level on the dash.
And total usable fuel quantity from really full down to engine will sputter.


# Modern dash displays are effectively small computers, running software. That software can be revised from time to time by the factory. And perhaps altered during dealer servicing with software ‘updates’. The ‘same dash’ can display different readings (and different warning threshold) for the same fuel quantity inside the tank if the dash software is changed.

[Mr. GP1800]

What I discovered is that with the ski sitting on a shop cart in my garage I could put 16 gallons into the tank. Maybe I could squeezed up to a half gallon more if I really tried for it. But I went for tank capacity with a reasonable amount of effort and not wasting 15 minutes trying to squeeze in just that little extra.

My dealer told me he put 3 gallons in the tank before delivery. If that’s the case you can probably put in close to 18 gallons in a bone dry tank. However after pumping the tank to the point where the fuel pump would no longer pump fuel I could only put in 16 gallons. That says the usable fuel capacity is 16 gallons. Probably more like 15 gallons when you take into account fuel moving around in the tank while riding the machine.

I filled the tank to full and then proceeded to pump out exactly 10 gallons of fuel to see where the gauge would read. That’s the 16.7% level the gauge showed. At that point you should have 5-6 gallons of usable fuel in the tank. At 10% remaining on the gauge is when the alarm sounds. From my testing that should be around 11 gallons used. Maybe less because of fuel movement in the tank while riding.

Attached are my notes from my testing and the actual fuel amount in the tank for each bar on the gauge. The bummer here is that the fuel gauge doesn’t even move or register a change in fuel level until there are 13 gallons remaining in the tank. So from 13 gallons to full capacity of the tank the gauge will show full. That’s why it seems to run a while showing full then drop towards empty rapidly.

[musubi]

What's the best way to carry and secure a 5 litre fuel container on board of these skis, including if you are doing jumps/rough water etc?

Try and find something that fits in the space under the rear seat (the waterproof one)?

Check out my post on my aux tank in my build.

https://www.greenhulk.net/forum/personal-watercraft-performance-skis/yamaha-pwc-performance/yamaha-projects-build-threads/283208-#post283208

This is a 6 gallon (22+ liters) tank. Scepter brand. It does scrunch the fuel fill tube a little, but has not given me issued filling. Easy to install and doesn't take much room at all. I secure it with straps from the stock fuel tank strap connections to the fire extinguisher strap connection. I don't intentionally ride my ski hard, but it has taken small jumps and constant rough sea rides with no issues. Siphons gas by itself.

I realize the situation here with Yamaha and it does suck since I care a lot about my extended range. But, I'd still choose a WaveRunner doing it again and I still think it's more than worth it to have what we have, regardless of the tank size and alarm issue. To me, just add a 3 gallon aux tank to the front, call it good, and now you're back to "stock" capacity and a bit more.

[not2fast]

What I discovered is that with the ski sitting on a shop cart in my garage I could put 16 gallons into the tank. Maybe I could squeezed up to a half gallon more if I really tried for it. But I went for tank capacity with a reasonable amount of effort and not wasting 15 minutes trying to squeeze in just that little extra.

My dealer told me he put 3 gallons in the tank before delivery. If that’s the case you can probably put in close to 18 gallons in a bone dry tank. However after pumping the tank to the point where the fuel pump would no longer pump fuel I could only put in 16 gallons. That says the usable fuel capacity is 16 gallons. Probably more like 15 gallons when you take into account fuel moving around in the tank while riding the machine.

I filled the tank to full and then proceeded to pump out exactly 10 gallons of fuel to see where the gauge would read. That’s the 16.7% level the gauge showed. At that point you should have 5-6 gallons of usable fuel in the tank. At 10% remaining on the gauge is when the alarm sounds. From my testing that should be around 11 gallons used. Maybe less because of fuel movement in the tank while riding.

Attached are my notes from my testing and the actual fuel amount in the tank for each bar on the gauge. The bummer here is that the fuel gauge doesn’t even move or register a change in fuel level until there are 13 gallons remaining in the tank. So from 13 gallons to full capacity of the tank the gauge will show full. That’s why it seems to run a while showing full then drop towards empty rapidly.

Great post.

[Mr. GP1800]

I’ve done a little more work with this. I think I have the whole issue figured out. There are several things going on here.

1. I removed the check valve from the filler neck and I was able to get more fuel into the tank. After looking closely at that check valve it appears the design of it is to prevent overfilling the tank. If you look at it closely, the float inside of it is cone shaped at the top where it closes off and doesn’t allow any more fuel in. With that valve in the tank I could only get 16 gallons in the tank. After removing it I could get 17.5 gallons in from completely empty. When I say completely empty, this is from pumping the tank as low as it would go to the point where the fuel pump could no longer pump fuel. I then used my fluid evaluator to pull out the remaining fuel. There were 3 more liters in the tank, or approximately 3 quarts for those who are not bilingual. The ski is on a cart in my garage and pretty much level, maybe even ever so slightly nose down. I suspect on a trailer I could squeeze a little more fuel in it. So the fuel capacity isn’t as big of an issue as I thought it is.

2. The fuel sender is weird. It’s not a variable resistance output, but a stepped output. It doesn’t start to move lower until the fuel remaining in the tank is around 13 gallons. So you ride around with a full tank and the gauge doesn’t show any movement until you’ve burned off 4 or 5 gallons depending on how full the tank was. I was able to measure remaining fuel at each level of fuel remaining on the gauge. Here is how that calculates out. These numbers are for usable fuel in the tank not counting the 3 liters or so that the pump can’t reach

7/8. 12 gallons
3/4. 10.5 gallons
5/8. 9.25 gallons
1/2. 8.5 gallons
3/8. 7.5 gallons
1/4. 6.5 gallons

When the gauge shows 2 yellow bars there are 5.5 gallons in the tank. The alarm is designed to go off when the dash sees 10% fuel remaining maybe around 5 gallons. The problem with this is that there is no buffering built into the gauge itself. It responds instantly to fuel float movement. So as soon as that fuel moves around in the tank and the float drops low enough to trigger the alarm, the beeper keeps going off. Unless you stop the ski and let the fuel level out again. But as soon as you move it’s going to make the alarm go off. When the alarm goes off there are still 2 steps left for the fuel sender to read lower fuel levels

3. I have a solution to this that I just finished putting together on my ski. If you have a Garmin unit or other brand chart plotter with NMEA 2000 capability, you can set up your own fuel level reading to display on the Garmin screen. I used the Garmin GFL-10 fluid level monitoring device. This connects to an NMEA 2000 network that you set up with the Garmin unit. Other chart plotter manufacturers have a similar device available. Once it’s all connected and set up, there are 8 calibration points you can program to the device.

I started with an empty tank and filled the tank using my 5 gallon square race jug with fuel quantity markings on the side of it. It’s graduated in 1/2 gallon increments. Below 4 gallons in the tank is the lowest fuel level the fuel sender will read. I calibrated this point to be 16% fuel remaining. When the gauge gets to this point it cant read any lower. I then added fuel a little at a time watching for fuel sender output with the gauge in diagnostic mode. This screen will show fuel sender output as a 0-100% reading. While adding fuel I watched this screen to see where the next step in the sender output occurred. I also had the garmin screen on watching the percent remaining on the garmin display and entered a new calibration point if the 2 numbers varied too much. I also compared these readings to the actual fuel in the tank based off the percentage of 18 gallons remaining. I probably programmed 6 calibration points of the 8 available overall.

The Garmin display can be set up to show percent of fuel remaining or actual gallons remaining. It turned out to be accurate to within .1 or .2 gallons of displayed fuel level versus actual. I think this is the best solution out there to deal with this crappy fuel gauge setup.

The parts needed to do this are the Garmin GFL 10 fluid level sensor and a Garmin NMEA 2000 starter kit. That includes the cables and fittings needed to make the NMEA 2000 network. The GFL 10 can be had for around $175 and the NMEA 2000 starter kit is about $85 online. You’ll then need to make some connections to get it all up and going. You’ll need to connect the NMEA 2000 network to switched power, and the GFL 10 to the fuel sender wires to the dash. THe easiest way to connect to the fuel sender wire is with a posi tap. I made a plug in wire harness to do the same thing, but the degree of difficulty with making the harness is higher. I also need to make a small plug and play harness to connect the switched power to the NMEA 2000 network. I may even build these for people to sell if there’s enough interest.

Here’s a few pics of what I was looking at and what the display looks like when all set up and working

[Kingsfan33]

About the 2023’s I saw a comment on the fuel alarm on a YouTube video from viewer who said; “You can mute it every fifteen minutes on the 2023 fx but youhave to come off throttle.”
To be able to silence it for 15 minutes at a time would be a positive thing!
Can anyone either confirm or deny this for the 2023 FX’s ?

Any update on being able to cancel the alarm for 15 minutes? If successful, please share how to do this?
Thx

[musubi]

I’ve done a little more work with this. I think I have the whole issue figured out. There are several things going on here.

1. I removed the check valve from the filler neck and I was able to get more fuel into the tank. After looking closely at that check valve it appears the design of it is to prevent overfilling the tank. If you look at it closely, the float inside of it is cone shaped at the top where it closes off and doesn’t allow any more fuel in. With that valve in the tank I could only get 16 gallons in the tank. After removing it I could get 17.5 gallons in from completely empty. When I say completely empty, this is from pumping the tank as low as it would go to the point where the fuel pump could no longer pump fuel. I then used my fluid evaluator to pull out the remaining fuel. There were 3 more liters in the tank, or approximately 3 quarts for those who are not bilingual. The ski is on a cart in my garage and pretty much level, maybe even ever so slightly nose down. I suspect on a trailer I could squeeze a little more fuel in it. So the fuel capacity isn’t as big of an issue as I thought it is.

2. The fuel sender is weird. It’s not a variable resistance output, but a stepped output. It doesn’t start to move lower until the fuel remaining in the tank is around 13 gallons. So you ride around with a full tank and the gauge doesn’t show any movement until you’ve burned off 4 or 5 gallons depending on how full the tank was. I was able to measure remaining fuel at each level of fuel remaining on the gauge. Here is how that calculates out. These numbers are for usable fuel in the tank not counting the 3 liters or so that the pump can’t reach

7/8. 12 gallons
3/4. 10.5 gallons
5/8. 9.25 gallons
1/2. 8.5 gallons
3/8. 7.5 gallons
1/4. 6.5 gallons

When the gauge shows 2 yellow bars there are 5.5 gallons in the tank. The alarm is designed to go off when the dash sees 10% fuel remaining maybe around 5 gallons. The problem with this is that there is no buffering built into the gauge itself. It responds instantly to fuel float movement. So as soon as that fuel moves around in the tank and the float drops low enough to trigger the alarm, the beeper keeps going off. Unless you stop the ski and let the fuel level out again. But as soon as you move it’s going to make the alarm go off. When the alarm goes off there are still 2 steps left for the fuel sender to read lower fuel levels

3. I have a solution to this that I just finished putting together on my ski. If you have a Garmin unit or other brand chart plotter with NMEA 2000 capability, you can set up your own fuel level reading to display on the Garmin screen. I used the Garmin GFL-10 fluid level monitoring device. This connects to an NMEA 2000 network that you set up with the Garmin unit. Other chart plotter manufacturers have a similar device available. Once it’s all connected and set up, there are 8 calibration points you can program to the device.

I started with an empty tank and filled the tank using my 5 gallon square race jug with fuel quantity markings on the side of it. It’s graduated in 1/2 gallon increments. Below 4 gallons in the tank is the lowest fuel level the fuel sender will read. I calibrated this point to be 16% fuel remaining. When the gauge gets to this point it cant read any lower. I then added fuel a little at a time watching for fuel sender output with the gauge in diagnostic mode. This screen will show fuel sender output as a 0-100% reading. While adding fuel I watched this screen to see where the next step in the sender output occurred. I also had the garmin screen on watching the percent remaining on the garmin display and entered a new calibration point if the 2 numbers varied too much. I also compared these readings to the actual fuel in the tank based off the percentage of 18 gallons remaining. I probably programmed 6 calibration points of the 8 available overall.

The Garmin display can be set up to show percent of fuel remaining or actual gallons remaining. It turned out to be accurate to within .1 or .2 gallons of displayed fuel level versus actual. I think this is the best solution out there to deal with this crappy fuel gauge setup.

The parts needed to do this are the Garmin GFL 10 fluid level sensor and a Garmin NMEA 2000 starter kit. That includes the cables and fittings needed to make the NMEA 2000 network. The GFL 10 can be had for around $175 and the NMEA 2000 starter kit is about $85 online. You’ll then need to make some connections to get it all up and going. You’ll need to connect the NMEA 2000 network to switched power, and the GFL 10 to the fuel sender wires to the dash. THe easiest way to connect to the fuel sender wire is with a posi tap. I made a plug in wire harness to do the same thing, but the degree of difficulty with making the harness is higher. I also need to make a small plug and play harness to connect the switched power to the NMEA 2000 network. I may even build these for people to sell if there’s enough interest.

Here’s a few pics of what I was looking at and what the display looks like when all set up and working

Thanks for going through the trouble of picking this apart.
So I have a few questions:

- Being this is connected to the fuel sender unit only and the arm has a limited range, am I understanding correctly that the GFL10 will only allow a more accurate reading of fuel remaining between 4 and 13 gallons of usable fuel in the tank? For example, will it read an accurate fuel amount if you used 2 gallons from full?

- How did you find the fuel sending wires? Did you just follow it from the tank top?

- Could you post the pictures you mentioned in your last sentence? I couldn't see them load on my end.

- Going forward, are you planning to leave the check valve out? 1.5 gallons is quite a bit to gain.

[Mr. GP1800]

Thanks for going through the trouble of picking this apart.
So I have a few questions:

- Being this is connected to the fuel sender unit only and the arm has a limited range, am I understanding correctly that the GFL10 will only allow a more accurate reading of fuel remaining between 4 and 13 gallons of usable fuel in the tank? For example, will it read an accurate fuel amount if you used 2 gallons from full?

- How did you find the fuel sending wires? Did you just follow it from the tank top?

- Could you post the pictures you mentioned in your last sentence? I couldn't see them load on my end.

- Going forward, are you planning to leave the check valve out? 1.5 gallons is quite a bit to gain.

That is correct. The fuel sender in the tank will only give you readings between 4 and 13 gallons in the tank. However, there are 2 levels that the sender will read at low levels in the tank that the dash almost ignores. The GFL 10 will let you know beyond when the buzzer sounds how much fuel you have remaining. By the time youre down to 4 gallons remaining in the tank you better be getting back anyways. Keep in mind, roughly a gallon of fuel in the tank is unusable.

The fuel sender wires are the black plug on the fuel pump.

I will be leaving the check valve out for sure. I see no reason to keep it.

[musubi]

The Garmin GFS 10 wont handle the fuel pressure put out by the fuel pump to the fuel rail. You can install the GFL 10 and calibrate it to show fuel level on the garmin to make the fuel gauge more accurate. I have done this before. It allows you up to 8 calibration points so you should be able to make it pretty accurate. You can then set up the garmin to show percent remaining right on your navigation screen.

When you say the GFS won't handle the fuel pressure, does that mean the GFS will misread, or that it'll break?

[Mr. GP1800]

When you say the GFS won't handle the fuel pressure, does that mean the GFS will misread, or that it'll break?

It says specifically in the instructions that it’s not for fuel injection pressures. I can’t remember the specific number but I want to say it’s over 10 psi. You’ll probably damage the sensor.

[musubi]

It says specifically in the instructions that it’s not for fuel injection pressures. I can’t remember the specific number but I want to say it’s over 10 psi. You’ll probably damage the sensor.

The instructions say "On pressurized fuel injected systems, the GFS 10 must be mounted on the low pressure side of the high-pressure fuel pump". Is our fuel pump considered high-pressure?

The instructions also mention the Max Back Pressure at 0.5 psi @ 20 gph and 1 psi at 40 gph. I'm guessing our system puts out more than this between the fuel rail and the pump?

[Mr. GP1800]

The instructions say "On pressurized fuel injected systems, the GFS 10 must be mounted on the low pressure side of the high-pressure fuel pump". Is our fuel pump considered high-pressure?

The instructions also mention the Max Back Pressure at 0.5 psi @ 20 gph and 1 psi at 40 gph. I'm guessing our system puts out more than this between the fuel rail and the pump?

I don’t know the number but I think stock fuel pressure is around 50 psi. 54 seems to ring a bell

[Reggie182]

Is anyone aware of if or what yamaha will be doing about this then?