Fuel Gauge Problem

[Ray]

My fuel gauge goes straight to "Full" as soon as the ignition is switched on.

I have a dipstick which suggests half a tank.

I hope to have a look at this problem tomorrow or Monday and wondered if anyone had tips of what and where to look first? So far I only know where the gauge is and the general area of the tank!

The boat is a Broom 29 and the gauge is an aftermarket addition professionally fitted but when and by who isn't known.

[ZimbiIV]

Could be a sticky float, go over Breydon when it's a bit choppy.

Always worked on Zimbi, it often stuck after being stood over winter with the tank full.

paul

[Ray]

Yes, she has been static for a number of months. Crossed Breydon Thursday and it was calm as a mill pond so may have to simulate waves 🙂

[Smoggy]

If it goes straight to the very top I reckon you have a bad connection, disconnect a euro gauge and they go full deflection.

I also have a dipstick and all it suggests is go to the pub, oh yeah that's me.....

[Ray]

1 minute ago, Smoggy said:

I also have a dipstick and all it suggests is go to the pub, oh yeah that's me.....

Sounds good to me 🍺 👍

[CambridgeCabby]

I too have one of those “pub dipsticks”,  trouble is that it never seems to say full when I’m in the pub 

[annv]

Hi Ray disconnect the wire from sender in tank,  switch on if still max gauge faulty if no movement replace wire and remove wire from sender in tank,there may also be a earth wire connected to body of sender,  if still max you have a short on sender wire to gauge,  if not and no movement fault is with sender,  remove sender from tank,  connect wire and GENTLY move float arm if it still shows max faulty sender,  remove the cover on sender and check the winding's and finger, clean/repair or replace. The sender works by  the finger rubbing on the coiled wire spool from top to bottom which is connected to a wire arm with a plastic float on the end thus altering the resistance to the gauge via earth, or you may have a plastic tubercle sender that works digitally not repairable. John

[Ray]

Many thanks John, that's very helpful 👍

[Smoggy]

I think the last tips may be the wrong way round, my water gauge has a dodgy connection and it goes to max when it's DISconnected, that is the euro resistance system (volvo gauges), US resistances work other way round with a different ohms range.

I made up some flyleads with resistors in to check my fuel gauges, one for empty, one for middle, and one for full.

[Ray]

By crawling into the bilge and laying across the engine I could just see the sender under the deck using a torch... a lifetime of beer and pies meant it remained out of reach sadly 😂

Luckily the boatyard has a helpful, thin young trainee who wasn't in today but may well have a job assignment before long 👍🙂

[annv]

Hi Ray why not remove dash and check gauge first it may be easier. John

[Ray]

Good idea John, thank you. Going back in the morning so that's my first job now 👍

[annv]

Just  accurd to me is there a access hatch to fuel sender that is on top of tank?. John

[Ray]

Doesn't seem to be John, the boat is a Broom 29 and I think the fuel gauge is a later addition. Having said that I wonder why it was put in such an inaccessible place, there are certainly more accessible areas of the tank!

[annv]

Hi Ray When a sender is fitted to a tank it tends to be fitted near the side to allow the arm with the float on the end to have a unrestricted arc from top to bottom the length of the arm is 3/4 or more the depth of tank plus there may be a baffle inside tank to stop/restrict surging of fuel, i hope there is enough space to remove sender rather then having to remove tank if this becomes necessary if not a wiring fault. John

[Ray]

Thanks John, I understand the whole setup a lot better now thanks to you 👍

I have a dipstick for the time being thank goodness so it's not urgent.