Fuel Gauge Sender Problems
My fuel tank sending unit
just failed and I have ordered a new one. How hard is it to replace?
Allen
Kalen #453
Depending on how flexible
you are, it's technically quite easy. If
you're frequently invited sailing because you're "good to have on the
rail" or can reach up and touch the first spreader, then it may not be
very comfortable doing this job. :)
You'll need a phillips screwdriver and .... that's it... :) However,
because of the position of the shelf covering the fuel tank, you may need one
of those bent screwdrivers. (I used a
socket wrench with a phillips
screwdriver socket and I think that is the best solution).
There are 5 screws to
remove, and a rubber gasket. I'd recommend that you take a black marker and
draw a reference mark to mark the orientation of the cover.
Also mark the gasket so that
you get them all back in the right orientation.
The cover will only go on only one way, but you'll be able to get a few
screws started with it on wrong and it's a bit tricky to get it re-oriented
otherwise.
Make sure that you put the
new sending unit on in exactly the same orientation as the old one. If it's rotated 90 degrees then the float may
hit the side of the tank and not read correctly.
I didn't use any goop or
sealer as the rubber gasket seems to do the trick.
Others may have some other
experiences to add.
-Jeff Hare
Here's how I fixed the float
problem on my boat.
On some boats, the float
assembly in the tank was put in incorrectly and is not too difficult to
correct. (although
those experienced at yoga will find it easier).
BACKGROUND ON THE FLOAT
ASSEMBLY: (The windy version...)
==================================
The float assembly in the
cat320 fuel tank is a pivot style float.
On the top of the tank, there is a round plate with 5 or 6 screws. The sender is attached to the bottom side of
this plate. The float arm is a long
stiff metal rod with a chunk of foam on the far end, which pivots at the
sender.
For purposes of
illustration,
* When the tank is empty, the float arm hangs almost
straight down.
* When the tank is full, the float arm is floating
horizontally and touches the top of the tank.
So, as you can see, the arm
must have nearly a full 90 degree unobstructed swing.
NOW A SOLUTION:
===============
On my boat, the float was
installed when the tank was empty (as is
common),so the float swung down
and hit the bottom of the tank. The
problem was that thefloat assembly was installed
facing the wrong direction, so it would simply float up a little and hit the
side of the tank and stop. If the tank
was a foot wider, it wouldn't be an issue. :)
The real problem was that the metal plate holding the sender is only tapped to go back on
facing one direction. ie: the screws are placed in an
odd pattern. After struggling with this
for an hour, I realized that I could actually loosen the set screw(s) on the
sender and rotate the sender 90 degrees itself.
Sheesh... Felt pretty stupid then.
For tanks which seem to
stick near full, this isn't likely the problem
because I can't see how anything
but a bad/stuck sender could prevent the float from swinging down.
For tanks that never seem to
read full, it's worth checking to see if the Float still floats...
I suppose, once you have the
float out, you could turn on the key and swing The
float from one extreme to the other and see if the gauge responds. If you have to swing the float pointing up
past horizontal in order to get the gauge to read full, you may need to put a
little downward bend in the float wire near the pivot point.
Just my $.02...
-Jeff Hare.
PS: Mr. Douglas called me at work and walked me
through how this works and what the possible problems/solutions were. I had only mentioned the problem to my
dealer, and was pretty impressed with this quick response from the top.
PS#2: Tool tip. If you have a socket wrench, get a small
socket whichhas a phillips screwdriver bit in it. The location makes it difficult to get a
normal screwdriver in. (it can be done, but the phillips socket was so much easier). You can troubleshoot the system pretty
easily, sorry if I misunderstood your request.
A sudden failure can be diagnosed as follows:
There are three parts that
could fail.
1) The gauge itself (less likely)
2) The wiring between the
gauge and fuel tank (more likely)
3) The tank sender/float
assembly (more likely)
To troubleshoot the Gauge:
Open the instrument panel, locate the fuel
gauge and short the Sender terminal to ground.
It should read full scale if the gauge is working. If you disconnect the sender wire, it should
read empty. Contact Seaward Customer
service and they'll give you the exact procedure.
To troubleshoot the sender
wire:
First, remove the sender wire (spade lug)
from the fuel tank and clean or replace the spade lug and connector. Clean terminals are crucial here because the
gauge specifically reads resistance and will be off if the connections are not
perfect. Also make sure the Ground
wire is equally good. You need an ohm meter to check the wires to
ensure that they don't have excessive resistance due to corrosion or chafe
somewhere.
To trouble shoot the sender
itself:
That's what I suggested by
removing the sender and moving it the full range of motion and watching the
gauge to be sure it is reading correctly.
Since yours was working and
recently stopped working properly, I would
follow the testing procedures in
the order I outlined above (If I were doing it myself).
Cheers and good luck!
Larry
WindSwept C320 #246
Below are my own archives of
listee comments...
Rick, Echo #488
I just completed
troubleshooting my fuel gauge and wound up replacing the sender, which fixed
the problem. As Dick points out, Seaward
has a
troubleshooting process, and it is also
available on the net at
www.teleflex.com. It is in the FAQ part of the marine
electrical page. It is very good and
will allow you to determine if the problem is the gauge or sender. If both check out okay then there may be a
wiring problem between the two.
I purchased the new sender
from Catalina. The advantage of getting
from Catalina is that the sender is a drop in (no pun intended)
replacement. Bad part is Catalina parts is getting more and more difficult to deal with. Don't know if sender is available from
Seaward.
Glad to share tips on
replacement of sender if you need them, although I will be away from email for
a week beginning on the fourth. We are
going boating!
I also got a lot of help
from this list, unfortunately I didn't keep the On the
top right corner on Page 295 of the West catalog is a "Teleflex"
'Universal electric fuel gage and sending unit". All you need is the
sending unit Model # 547406 TELEF#90424P which at that time cost $29.99. I
didn't check the West electronic catalog but I'll betcha
you can get it from there as well.
Regards
Dave of Jalapeņo (#414)
The gas gauge has remained
on "full" even though we have put 12 hours on the engine. When we refilled diesel, we found it had used
4.2 gallons. Does anyone know what we
should check and where that item
is located? I assume either the gauge is stuck or the
sender is bad but I don't know where to look.
Chris Burti
"Commitment"
Catalina 320, #867,
Just been
through this.
The gauge is simply an ohm meter and the sender' a variable resistor. If it is
reading full the gauge is bad or, most probably, there is a short in the wire
from the tank to the gauge.
Open the instrument pod, disconnect the wire from the gauge to the tank. If the
gauge drops to empty, disconnect the wire from the tank to eliminate any chance
the short will affect the test and run a jumper
wire from the sender to the
gauge. If it reads appropriately you've found the problem.
To test the sender, it
should read 0 ohms full and 120 ohms empty. If you are getting these readings you
are fine.
If the sender is fine and
the wire is fine, then your gauge is bad.
Chris
Well this has turned into an interesting project. For those late to the telling, my fuel gauge is reading 'Full' all of the time, so I replaced my float unit in the tank and that didn't cure the problem.
With no input from the list on my query as to whether there was any advice other than 'replace the gauge', I turned to Catalina to order a new gauge. They promptly referred me to Seaward where I wound up with Lonnie (562-699-7997 ext. 213). He was extremely helpful to me and when I expressed my intention of posting this report to this list, he volunteered that I should provide his contact information in the event anyone had further questions. They are very proud of their products at Seaward and clearly dedicated to customer service.
It seems that Lonnie believes that there are far too many change-outs that are simply the result of faulty wiring.
First, 'sending unit' is a misnomer. The gauge is merely a volt/ohm meter and the float unit a variable resistor. It runs from zero ohms at full to 240 ohms at empty.
If the float isn't stuck, the following is the test protocol. We will assume a half-full fuel tank and that you have removed the float unit to check to see that it isn't stuck or that the wires haven't come loose.
If the gauge is reading 'Empty' all of the time, the most likely culprit is a bad ground connection, second would be a break in the hot wire, and last a faulty float unit. Check the connections and if that doesn't cure the problem, test the wiring by running a jumper from the negative (black) stud on the gauge to a solid ground. On our Catalinas, a bad ground could affect all the instruments in the pod unless the problem is only at the tank connections. Since you can see in the tank when you check to see if the float is stuck, you will have an approximate idea of how much fuel is in the tank. Mine is about half full. Testing the float unit with the ohm meter after it was reinstalled gave a reading of 98 ohms. This corresponds to a little less than half full and indicates that my new float unit is operating properly (as the old one probably was).
If the gauge is reading 'Full' all of the time, the most likely culprit is a short to ground in the positve lead from the tank to to the gauge (pink on my 2001 320). The diagnostic test for the gauge is to disconnect the gauge from the positive wire to the tank and turn the key on. If the gauge now reads 'Empty' a short is likely. Disconnect the positive wire from the tank. Do a continuity test from the wire to ground. If no short circuit is indicated, run a jumper from the positive contact on the gauge to the postive (center) stud on the float unit (make sure the old positive wire is still disconnected). Turn on the key and if the gauge still reads 'Full', the gauge is defective. This result, it seems, is extremely rare for the folks at Seawards technical support.
Unfortunately, such is the case in my situation. The good news is that the folks at Seaward have exceeded my expectations in helping to resolve that issue as well. They really do deserve kudos.
On a side note. Finding the folks at Catalina unusually (in my experience) responsive to my email inquiry in this regard, I reposted my inquiry about the uncured whit coating in the interior lockers (FWIW, I have only tried to contact them by email. In all fairness, list members touting their responsiveness have been reporting the results of phone conversations so I probably should have called.). My contact, Mr. Robert Butler, resonded promptly but allowed as that wasn't his area of expertise and that he would refer my inquiry to Mr. Frank Butler. I allowed as that as his reputation for customer service was excellent that I appreciatied the help.
It has been two days and I have heard not nary a whisper from Mr. B. I can only conclude that either Catalina is responsive to issues that they care to address and studiously ignores issues thay don't...or that Mr. B is a techniphobe, won't use email and I'm not going to get any help unless I phone him. I suspect that the latter is the case as he renowned for his personal attention to customer complaints, yet the various posts from "Catalina" that occasionally appear on this list in response to some factory issue have been from Jerry Douglas (as my poor recollection leads me to believe).
If anyone has friends at court, I really am getting a bit
tired of having to wrap stuff in plastic to keep the white goo
from sticking and I am not callin
Chris Burti
"Commitment"
Catalina 320, #867,