Fuel Gauge

[aquacraig@shaw.ca]

Shellani's port fuel gauge is suddenly not reading properly...I hope! Was cruising yesterday and the gauge was reading empty. Didn't even check it b4 leaving the dock as refuelled only 40 hours ago. The forward tank companionway gauge shows 3/4 full. Probably an electrical issue so where do I start looking/checking?
Thanx

 

[Glory]

If you disconnect the fuel sender and short out the gauge lead to the ground and the gauge goes to full, it is likely the sender. then remove the sender and test it when it is out of the tank. You may even find the float missing, an easy fix.

JM

 

[aquacraig@shaw.ca]

Just so I understand..I disconnect the wire from the "tank" end and then cross a wire across the gauge? This should
show "full". One other question, what is the socket size for the gauge. Looks like 2 3/8". Thanx

 

[Fanfare]

If your senders on top of the tanks are like mine you will need to mark their position with a marker on the sender and on the tank because they only go back in one way. Mine are like a gas fuel pump, although these have several layers to align. If you replace the sender improperly one out of the five screws won't align and fuel will leak past the gasket.

This will save you the pleasure of rotating the sender one hole and tightening four screws only to find it still isn't right.

 

[Glory]

Just so I understand..I disconnect the wire from the "tank" end and then cross a wire across the gauge? This should
show "full". One other question, what is the socket size for the gauge. Looks like 2 3/8". Thanx

the gauge will have a gauge wire and a ground wire connected to the sender anchor bolts. Connect both wires and if the gauge moves to full it sounds like the gauge is OK. Then remove the sender and check ot as indacated above.

Good luck.

JM

 

[aquacraig@shaw.ca]

OK Now I understand. Sorry for being a bit dense!
Craig

 

[Nonchalant1]

Is it your forward or aft tank? You don't really have port and SB tanks, they are fwd and aft and you set which engine draws from which tank with the fuel manifold levers. Normally, only the fwd tank has a gauge, depending on how old your boat is.

First, most of the senders have a manual reading on the sender on top of the tank. Just a little red arrow to indicate fuel level. If that is working, then the tank float and spiral is OK. If the helm gauge does not read the same as the red arrow, the problem is in the sensor, the wires or the helm gauge. Do as suggested and connect the 2 wires to see if the helm goes to full. New senders are available from the original supplier, and maybe Sam's.

If the red arrow is not there or not working, check all 3 of your water tank tops for a working manual reader or sender (same sender). They all have that float & spiral gauge and dish top sender. Move the working sender to the fuel tank and if it works, get a new sender.

The original fuel gauge nut is the same size as your prop nuts. If you have a socket for your prop nuts, use it on the gauge. It takes a LOT of torque to turn an old original gauge nut. However, you can remove the sender just by undoing the screw and lifting it out. It is magnetically connected to the tank float spiral through the brass dish the sender sits in.

Don't remove the tank float and spiral if you have a full tank of fuel, because it can gush fuel out if the level of the boat has fuel at the top of the tank in that position. I have fixed a bad cork in the spiral for the gauge by making a new one. Use real cork due to diesel fuel melting some synthetics. Replacement gauge and spirals are not available.

Doug