Need interpretation of fuel baffle float ohm test results

[kilgorekb]

1) Grounded out the fuel gauge. Gauge read Full.

2) Removed float. Float has fuel inside. 1 magnet has lost its zinc? coating, but it's still a magnet.

3) Performed resistance test with fuel-filled float. Set multimeter to 200 Ohm.
3a) Float at bottom = 00.1
3b) Float 1 inch from bottom = 00.2
3c) Float 2 inches from bottom = 00.4
3d) Float anywhere above 2 inches= 1

Can someone tell me what these results mean?

 

[LouDoo]

I don't have an answer, the readings should be in the shop manual. If you just replace the float it will most likely fix your problem, the float is the problem about 95% of the time, 100% for me.

Lou

 

[Seadoobuddy]

1) Grounded out the fuel gauge. Gauge read Full.

2) Removed float. Float has fuel inside. 1 magnet has lost its zinc? coating, but it's still a magnet.

3) Performed resistance test with fuel-filled float. Set multimeter to 200 Ohm.
3a) Float at bottom = 00.1
3b) Float 1 inch from bottom = 00.2
3c) Float 2 inches from bottom = 00.4
3d) Float anywhere above 2 inches= 1

Can someone tell me what these results mean?

That doesn't sound right...should in increments of about 10.
On my 787 it reads 0 resistance on Ohm at near empty, 17.8, 27.8, 37.8, 47.8, 57.8 ,67.8, 77.8, then 89.8+/-0.9 at full.
The books lists several models but each is really close to these numbers.

 

[Sportster-2001-951C-Stock]

Might try 50 Ohm scale?

Sounds like it's working though, reconnect the gauge and slide the float up and down to confirm?

Fuel in float of course is no-go. I had some in mine and drilled hole in the end at suspected leak to drain it out, put a small screw in the hole and working fine for two years. Screw is in down position now, to trap air in case of small leak, I don't think it does though.

My root cause for disassembly was the fuse on upper portion of circuit board.

Edit:

On second thought, I agree with seadoobuddy, should be near 100 ohm max resistance, not 1 Ohm. Probably a stuck magnetic reed switch.

 

[kilgorekb]

Redid the test with a fluke and tried all scales. Basically, I have continuity for a few inches, and then just a millimeter further up, the resistance goes to infinity.

 

[Sportster-2001-951C-Stock]

There are a series of glass tube magnetic reed switches mounted on the circuit board, each of these switches is in series with a resistor of increasing value. So, depending on the position of the magnetic float, the reed switches nearest the float will close and make a circuit through it's resistor and give you the value corresponding to the position of the float.

Sounds like you've got something wrong with the circuit board, infinity is an open circuit.

I once had a stuck reed switch which I was able to get unstuck by rapidly moving the magnet up and down the tube. Afterward, the fuel sensor worked perfectly until the day I sold the ski about 10 years later.

 

[Seadoobuddy]

Try the hick-billy way....either use duct tape to hold something together or whack it
OK, better not whack it too hard

The book says to put the meter on R X 1 scale....touch the leads to zero the meter. connect the meter leads to the fuel sender switch leads.
Measure from the bottom of the mounting flange.

 

[Sportster-2001-951C-Stock]

It appears you've found the problem (malfunctioning sensor). Any ohmmeter set on 200 Ohm scale can measure 100 Ohms and down to less than 20. x1 scale for this range would of course be more precise, especially if you're using an analog meter.