can I fix my gas guage myself??

domindart · 12-28-2011, 10:46 PM

hello folks,

thought Id ask here,

I need to fix the gas guage on the scooter. A Tomos Nitro 150.

I think its the float

How can a beginner mechanic do this ?

Rather than having to wait till I can spend a good $200 or so to get it fixed.

It (the gauge) will go up to full sometimes, then read middle sometimes, then go to empty. Its basically (the needle) going whereever it wants.

thnx

chimper · 06-01-2012, 10:14 AM

Mines doing the same thing - sucks. I hear the float is styrofoam and eventually sinks when it soaks up the fuel... doesn't make sense though. Im sure it would be a huge pain to do the job yourself, having to remove a lot of the plastics. You could just watch your mielage, but I hate not knowing how much gas I have left either. Also its good to clean out all the old gas, before you keep adding fresh.

chimper · 06-01-2012, 11:01 AM

Really hope I can figure out how to fix mine... :/ sucks not knowing at least a general idea of how much gas is left

Captonzap · 04-12-2013, 10:58 PM

Without seeing your setup, or a wiring diagram, I will just suggest a few things. Find your gas tank. Start with where you put the gas in, and see where the gas goes. That's the tank.

On the tank, there should be a part, unit, thingy, something that is fastened into the top of the tank, with either one or two wires coming out of the thing. See if you can figure out how to get it, the thingy, out of the tank. Some have screws holding them in, others have a twist and turn arrangement. (Don't break anything).
After you get it out, you should see a float that makes a slider move on a coil of wire. Put an ohm meter across the two wires, or across the one wire and the metal body of the part.
As you move the float up and down, you should see the resistance change. If it doesn't change the ohm reading, the sender is bad.

If it does change, put everything back the way you found it, and start chasing the color coded wires up to the gauge. Look for chaffed or broken insulation or wires. If you get the same readings on the wires up at the gauge plug , that you got at the sender, the gauge is probably bad.
The way most gauges work is that the gauge is fed some current, which travels through the gauge, through the wire to the sender, and the sender varies the resistance to ground, depending on the fuel level, which causes the gauge to read appropriately.
Check one of the wires to the gauge, and make sure that you are getting some voltage on one of the wires to the gauge, when the key is on.
There are other possible problems, but these tests will tell you a lot.
CZ

RiditAgain · 04-13-2013, 09:21 AM

If you have a trip odometer use that. Fixed now go ride!

12-28-2011, 10:46 PM	#1
domindart Verified Join Date: Nov 2007 Location: atlanta ga Posts: 68	can I fix my gas guage myself?? hello folks, thought Id ask here, I need to fix the gas guage on the scooter. A Tomos Nitro 150. I think its the float How can a beginner mechanic do this ? Rather than having to wait till I can spend a good $200 or so to get it fixed. It (the gauge) will go up to full sometimes, then read middle sometimes, then go to empty. Its basically (the needle) going whereever it wants. thnx __________________ 2009 tomos nitro 150 scooter

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06-01-2012, 10:14 AM	#2
chimper Verified Join Date: Jun 2012 Posts: 15	Mines doing the same thing - sucks. I hear the float is styrofoam and eventually sinks when it soaks up the fuel... doesn't make sense though. Im sure it would be a huge pain to do the job yourself, having to remove a lot of the plastics. You could just watch your mielage, but I hate not knowing how much gas I have left either. Also its good to clean out all the old gas, before you keep adding fresh.

06-01-2012, 11:01 AM	#3
chimper Verified Join Date: Jun 2012 Posts: 15	Really hope I can figure out how to fix mine... :/ sucks not knowing at least a general idea of how much gas is left

04-12-2013, 10:58 PM	#4
Captonzap Newbie Join Date: Apr 2013 Posts: 6	Without seeing your setup, or a wiring diagram, I will just suggest a few things. Find your gas tank. Start with where you put the gas in, and see where the gas goes. That's the tank. On the tank, there should be a part, unit, thingy, something that is fastened into the top of the tank, with either one or two wires coming out of the thing. See if you can figure out how to get it, the thingy, out of the tank. Some have screws holding them in, others have a twist and turn arrangement. (Don't break anything). After you get it out, you should see a float that makes a slider move on a coil of wire. Put an ohm meter across the two wires, or across the one wire and the metal body of the part. As you move the float up and down, you should see the resistance change. If it doesn't change the ohm reading, the sender is bad. If it does change, put everything back the way you found it, and start chasing the color coded wires up to the gauge. Look for chaffed or broken insulation or wires. If you get the same readings on the wires up at the gauge plug , that you got at the sender, the gauge is probably bad. The way most gauges work is that the gauge is fed some current, which travels through the gauge, through the wire to the sender, and the sender varies the resistance to ground, depending on the fuel level, which causes the gauge to read appropriately. Check one of the wires to the gauge, and make sure that you are getting some voltage on one of the wires to the gauge, when the key is on. There are other possible problems, but these tests will tell you a lot. CZ

04-13-2013, 09:21 AM	#5
RiditAgain Senior Member Join Date: Jul 2011 Location: Pennsylvania Posts: 1,276	If you have a trip odometer use that. Fixed now go ride!