[C320-list] Fuel Gauge Stuck on Full ... Robert and Joe

[Bruce Stanley]

Thaks guys ... info very helpful.
Regards from downunder
Bruce Stanley #1084 Sydney Australia

On Tue, Apr 1, 2008 at 1:43 AM, Robert E. Sloat <resloat at comcast.net> wrote:

> Bruce-Jeff and Chris have good advice.  I have hull 894 (2002) and my fuel
> gage got stuck on 3/4 full during the first season when the tank was less
> than that.  It turned out that the float on the fuel level sending unit in
> the tank was rubbing against the inside of the tank so it could not go
> down
> below 3/4 full.
>
> If all else fails on your testing check out if the float is lodged against
> the inside of the tank.  One my boat you could gently tap the port side of
> the tank with your fist and hear the float rattle against the tank.  I
> removed the sending unit (it is a tight fit and you need a short phillips
> screw driver to unscrew the unit) and rotated the sending unit 90 degrees
> away from the tank and eliminated the problem.  Before removal I marked
> the
> sending unit so I would know how it was originally installed if my
> analysis
> was not correct.  This problem was noted by a fuel owners in 2002 and some
> of the fixes were what I did.
>
> I rely on the gauge reading and also use the Dobbs meter to keep track of
> engine hours and fuel usage estimates and make sure the two are close on
> fuel usage. Since I use little fuel over a season, I try to run the tank
> to
> 1/4 full at the end of the season so I can load a fresh tank of fuel
> before
> winter storage.  When I get down to the 1/4 full mark, I also measure fuel
> level by tapping on the tank with the handle of a plastic screw driver to
> locate the fuel level.  With enough practice you can discern the
> difference
> in the taping sounds above and below the fuel level.
>
>
> ----- Original Message -----
> From: "Chris Burti" <clburti at gmail.com>
> To: <C320-List at catalina320.com>
> Sent: Monday, March 31, 2008 9:23 AM
> Subject: Re: [C320-list] Fuel Gauge Stuck on Full
>
>
> > *A common problem* In this case the gauge is a voltmeter and the float
> > mechanism in the tank is essentially a variable resistor. Voltage goes
> to
> > the tank sender, if the tank is full the circuit is almost open and the
> > gauge reads full. As the float drops, resistance increases, and the
> needle
> > drops correspondingly.
> >
> > If the problem is with the sender, it can be tested by removing the
> shelf
> > in
> > the starboard aft locker and removing all wires. Tested with an ohm
> meter
> > it
> > should read between 60 and 120 ohms. Open or closed circuit readings
> > indicate a failure of the unit.
> >
> > If that checks out and, as it sounds like from your description, the
> gauge
> > reads 'full' when not working, there may be a short in the circuit.
> > If the gauge reads 'empty' when not working, there may be a broken wire.
> >
> > If the sender is good and the wiring is good, that just leaves the gauge
> > to
> > be bad. You open the engine pod to do all this testing, disconnect the
> > pink
> > power lead from the gauge, it should then read "empty". If not, it is
> bad.
> > If it does read "empty", jump the power lead from the lights to the
> > terminal
> > for the tank lead (pink) and the gauge will read 'full' when you turn
> the
> > key on. Run a jumper from the tank to the gauge, if it reads correctly,
> > you
> > have a short in your sending wire (the most common problem according to
> > the
> > techie at Seaward"
> >
> > On Mon, Mar 31, 2008 at 9:44 AM, Jeff Hare <catalina at thehares.com>
> wrote:
> >
> >> Hi Bruce,
> >>
> >>  Actually, the fuel gauge circuit is very simple.  The fuel sender is
> >> simply a variable resistor.  That's all.
> >> Annie's correct about the fuel sender arm.
> >>
> >> 1) If it were installed incorrectly (rotated 90 degrees like mine was)
> it
> >> would not be stuck on full, instead the gauge would not be able to
> reach
> >> full.
> >> 2) If it ever worked properly, then it was installed correctly, so
> ignore
> >> #1
> >> 3) If it stopped working suddenly and is stuck either on full or empty,
> >> then
> >> this may indicate *either* a short or an open circuit, and I don't
> recall
> >> if
> >> a "short circuit" causes the gauge to read full or empty.
> >>
> >> * First, check the top of the tank where the fuel hoses enter and
> verify
> >> that the wires connecting to the tank sender are in good shape.
> >> * Next, remove the wheel and open the engine pod, and find the fuel
> >> gauge.
> >> * Ensure that the connections are in good shape.
> >> * Follow the sender wire(s) from the back of the gauge to the "terminal
> >> block" (where the wires come up through the tube from below).
> >> * Frequently this junction block is a problem.  I had loose wires, and
> >> other
> >> wires that were clamped on insulation not bare wire.
> >>
> >> Seaward provides the tanks and gauges for Catalina and they gave me a
> >> procedure for diagnosing the gauge many years back.  I don't have it
> >> anymore.  Perhaps someone can find the procedure from Seaward and send
> it
> >> to
> >> you, or I'll look for it if nobody steps up.
> >>
> >> On the back of the gauge, there is a power wire and a ground wire
> (maybe
> >> connected to the frames of all the gauges.)  This powers the
> backlighting
> >> of
> >> the gauges.  There will be 1 or 2 other wires connected to the back of
> >> the
> >> gauge, they go to the sender on the fuel tank.  Disconnect one of them
> >> and
> >> then see if the gauge goes to Empty.  If it does, then it indicates (I
> >> believe) that you probably have either bad sender.
> >>
> >> Replacing the sender is not a big deal, but here are a few tips:
> >>
> >> 1) Try not to do this with a full tank!  The emptier the better as
> you'll
> >> be
> >> able to diagnose whether it's really fixed or not.
> >>
> >> 2) Important:  Before Removing the plate on the top of the tank holding
> >> the
> >> sender, take a black marker and make a mark on orientation of the plate
> >> and
> >> the top of the fuel tank so that you get it oriented the same way
> during
> >> reassembly.  It only fits ONE way.  Any other orientation, you'll won't
> >> be
> >> able to get all 5 screws to align with their holes.  Close, but not
> >> quite.
> >> Took me a while to figure out that the holes weren't symmetrically
> >> placed,
> >> presumably to ensure that the sender goes in properly.
> >>
> >> 3) Use a Phillips screwdriver bit on a socket wrench to give you 90
> >> degrees
> >> access to the screws holding the cover and it's Easy.  Try a regular
> >> screwdriver and you'll fight with it.  Don't lose the screws!
> >>
> >> 4) Note the direction that the sender arm swings when removing it.
> >>
> >> 5) Keep some rags nearby to protect against drips, clean the seal
> really
> >> well before putting it back together.
> >>
> >> -Jeff
> >>
> >>
> >>
> >>
> >> -----Original Message-----
> >> From: c320-list-bounces at lists.catalina320.com
> >> [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Bruce
> >> Stanley
> >> Sent: Sunday, March 30, 2008 6:42 PM
> >> To: C320-List
> >> Subject: [C320-list] Fuel Gauge Stuck on Full
> >>
> >> The Fuel Gauge is Stuck on Full ... when it was 3/4 empty!
> >>
> >> any thoughts on fixing this the problem?
> >>
> >> thanks
> >> Bruce Stanley #1084/FantasticLady/Sydney Australia
> >>
> >>
> >
> >
> > --
> > Chris Burti
> > Farmville, NC
>
>