H-34 Manual Fuel Check

[YVRguy]

We have a Hunter 34 with no fuel gauge. (The PO had installed a Snake River system but it has never worked). For years we have been reliably estimating fuel levels based on the engine meter and a baseline of 1.8L / hour burn. Recently we had our engine rebuilt and then last week we had an incident where the engine quit while we were underway. By our standard calculations we should have been fine for fuel but there's a chance that after the rebuild our numbers are different. OR, it could just be the infamous clogged fuel line.

Anyway... all that to say that I'd like to eliminate the possibility that we ran out of fuel before we start looking at other problems. Issue is, we have no way to manually validate how much fuel is in the tank. Attempts at inserting a makeshift dipstick have not gone well. Any suggestions on how to check the fuel level?

Thanks in advance...

 

[danm1]

Because I am too fat or inflexible to get into the locker to service batteries, I cut a hole in the quarterberth wall for access. One other benefit is the side of (plastic?) the tank is exposed. I put a flashlight on top and can see the fuel level, which seems to be about 5/8th-3/4 inch per gallon. Not sure about your engine or prop, but with the original Yanmar and an old Martec two blade folder I can cruise at about 6 knots at about a gallon an hour.

 

[hunter34austin]

same here. previous owner did a hack job with the quarter berth wall. access to the locker from here is actually quite good (batteries, etc) so when I redid the wall I kept an access door. It's hinged with locks so it stays closed. Below is the only picture I have from when I did some rewiring, so ignore the cables, the door shuts completely and you can't really see it then.

 

[mnmpizza]

I installed a fuel gauge and ran it to the nav station.

others have simply placed the gauge near the tank.

 

[Claude L.-Auger]

YVRGuy, FYI I took a long cruise during summer of 2019 and burned 595,85 liters of fuel during 247,4 hours of the 3GM30F engine operation. An average of 2,42 liters per hour ! I cruise at roughly 80% of max RPM, which means most hours at 2650 to 2700 RPM. When using engine hours to keep an average, it's safer to err on the high side of consumption. 5 years ago I installed a WEMA gauge in the electrical panel. The sensor is the model as per pix, which seems more reliable than the folding arm style. Also shown is a picture of how I installed the sensor on the tank. I already had a 10'' SS inspection port, so it was a no-brainer to just put it there. Incidentally, I also cut an opening in the wall of the stern cabin, which helps quite a bit when having to do major work down in the dungeon !

 

[markwbird]

Fill it up.

 

[markwbird]

It sounds like you are trying to get pretty close to empty before refueling. That is probably not a good idea even if you do have a fuel gauge. Best to keep the tank as close to full as is reasonable (1/2 tank or better) as it reduces the air space above the fuel and thus the moisture that can get into the fuel and cause algae growth. Also use a biocide additive to prevent this. In my case, I fill the tank only once a year and even then, it only takes about 10 gallons on a 25 gallon tank.

 

[RoyS]

To keeping tank filled. Should you run into serious chop you may pick up air with a near empty tank and stall at a bad time.

 

[Artey1]

YVRGuy, FYI I took a long cruise during summer of 2019 and burned 595,85 liters of fuel during 247,4 hours of the 3GM30F engine operation. An average of 2,42 liters per hour ! I cruise at roughly 80% of max RPM, which means most hours at 2650 to 2700 RPM. When using engine hours to keep an average, it's safer to err on the high side of consumption. 5 years ago I installed a WEMA gauge in the electrical panel. The sensor is the model as per pix, which seems more reliable than the folding arm style. Also shown is a picture of how I installed the sensor on the tank. I already had a 10'' SS inspection port, so it was a no-brainer to just put it there. Incidentally, I also cut an opening in the wall of the stern cabin, which helps quite a bit when having to do major work down in the dungeon !

Claude, I see you completely cut your bulkhead in half and then redid it with a new piece of ply and cut your access hatch out of the new piece. Did you join the old and new pieces of ply? Is this bulkhead structural? Mine feels very flimsy and I'm suspecting due to damage from old binnacle leaks following wires which pass through this bulkhead. Interested on why and how you cut out and replaced that larger section.

Sorry to hijack the thread! I'm hoping to do an arduino or raspi tank monitor for mine. Hopefully external conductance or build a sonar housing. Code is all done and works well with a bucket in terms of accuracy, just have to figure out my sensor and housing.

 

[ggrizzard]

Artey, does Arduino make a fuel tank sensor?

 

[Artey1]

Artey, does Arduino make a fuel tank sensor?

No. Arduino doesn't make most of or any of the sensors that I'm aware of. They are all from different manufacturers and you just program your Arduino to read the resistances usually

 

[SabreToothedEngineer]

YVRGuy, FYI I took a long cruise during summer of 2019 and burned 595,85 liters of fuel during 247,4 hours of the 3GM30F engine operation. An average of 2,42 liters per hour ! I cruise at roughly 80% of max RPM, which means most hours at 2650 to 2700 RPM. When using engine hours to keep an average, it's safer to err on the high side of consumption. 5 years ago I installed a WEMA gauge in the electrical panel. The sensor is the model as per pix, which seems more reliable than the folding arm style. Also shown is a picture of how I installed the sensor on the tank. I already had a 10'' SS inspection port, so it was a no-brainer to just put it there. Incidentally, I also cut an opening in the wall of the stern cabin, which helps quite a bit when having to do major work down in the dungeon !

Hi Claude,

Do you remember what length sensor you bought?

 

[Claude L.-Auger]

Hi Claude,

Do you remember what length sensor you bought?

Where I installed it the tank is 16'' deep. The WEMA vertical float sensor was 15' which suited me just fine as it provided a little security by giving me a reading showing slightly less than what is actually left in the tank. My hourly average is still what I use to tell the pump operator what it will take when filling up. I'm usually almost dead on and therefore am able to avoid fuel spills.

 

[jssailem]

@SabreToothedEngineer It is an easy task to

1. remove the old sensor,
2. clip the wires,
3. stick a stick down into the tank,
4. mark the stick where it stands out of the tank,
5. Measure to the mark,
6. Buy a unit 1 inch less than measured,
7. Check the hole count and pattern so that you get the unit the matches,
8. Install unit and wire.
9. Test the fuel gauge.

Happy happy. Even I was able to do it.

 

[SabreToothedEngineer]

@SabreToothedEngineer It is an easy task to

1. remove the old sensor,
2. clip the wires,
3. stick a stick down into the tank,
4. mark the stick where it stands out of the tank,
5. Measure to the mark,
6. Buy a unit 1 inch less than measured,
7. Check the hole count and pattern so that you get the unit the matches,
8. Install unit and wire.
9. Test the fuel gauge.

Happy happy. Even I was able to do it.

Thanks for that. The only complication is that there is no existing sensor; hence the project to install one. I was a little concerned about drilling a hole in a tank full of diesel, but after a bunch of reading I've concluded that it can be done perfectly safely.

 

[jssailem]

I've concluded that it can be done perfectly safely.

Yes it can. Use a vacuum as you cut the hole to stop drill dust from falling into the hole.
All of the units I’ve seen provide a template to locate the screw holes.
Tap the screw holes and your nearly done.
Simple connections. And you’ll be a happy boater.