Jerry77 1,218 #1 Posted August 15, 2016 Down to the last repair on my 516h...fuel gauge shows 1/2 tank.sometimes more...took the sending unit out of the tank and ohm'd it - shorted througout its' travel...have the 12 volts at the tank, so the wiring is good...don't really know if the gauge is good or not, but I know the sending unit is not showing any resistance. Has anyone ever had any luck trying to rejuvinate the sending unit? Couldn't find any threads in the archives...thanks for leads...... Share this post Link to post Share on other sites
DougC 2,641 #2 Posted August 15, 2016 My Toro dealer told me the sending units have been discontinued for the 91 520H I take care of for my mother-in-law but didn't see why you couldn't use a car fuel gauge sending unit. I assume he meant replacing the OEM variable resistance potentiometer parts with the parts from the car unit. She has a medium size yard in town and for me it would be easier for my brother-in-law to take off the gas cap and fill the tank with gas before he mows her yard..... I guess I'm lucky my '88 and'95 520H fuel gauges still work properly. Make sure you have a good ground. A good ground is just as important as 12V at the sender for proper operation of the fuel gauge. Share this post Link to post Share on other sites
Jerry77 1,218 #3 Posted August 15, 2016 Got a good ground - the unit itself has no resistance - might be able to use an automotive one - read somewhere that the wh unit runs from 35 ohms to 265 ohms...I made one out of an old Studebaker work again, but it was much heavier duty and responded well to cleaning- don't really need it to work - just hate to have something not working....I may try to disassemble it - can't be any worse if I ruin it...was thinking that someone had already tried that....;) Share this post Link to post Share on other sites
cleat 6,004 #4 Posted August 16, 2016 I have tried, mostly without success to clean them up. The ones I have gotten that could not be saved were from gas tanks that had sat with bad gas for a long time. At this point the sender unit is a ball of rust that will never function again. I have picked up good used ones off of ebay and all of my 520's currently have working gas gauges None of mine will ever see ethanol if I can help it and that should help as well. 1 Share this post Link to post Share on other sites
Marty Taylor 4 #5 Posted October 30 On 8/15/2016 at 5:39 PM, Jerry77 said: Down to the last repair on my 516h...fuel gauge shows 1/2 tank.sometimes more...took the sending unit out of the tank and ohm'd it - shorted througout its' travel...have the 12 volts at the tank, so the wiring is good...don't really know if the gauge is good or not, but I know the sending unit is not showing any resistance. Has anyone ever had any luck trying to rejuvinate the sending unit? Couldn't find any threads in the archives...thanks for leads...... Hey Jerry... quick question for you. Had a new pump put on my 516-H this sping, Fuel guage not working and spoke to mechanic (he's an hour away) and he thinks he may have forgotten to reconnect the electrical connection near the fuel tank. He wanted me to bring it back, but I said I would try to reconnect. He stated I need to remove 6 bolts (remove seat and shrouding) to get to the tank. Can you provide me a description what exactly I need to. Semper Fi, brother Marty Taylor USMC Veteran (1970-1973) Share this post Link to post Share on other sites
cleat 6,004 #6 Posted October 30 (edited) Here is a picture showing all 8 bolts that must be removed. Disconnect the lift shock then pull the 4 bolts holding the seat pivot brackets near the front of the fender and lift off the seat assembly. Now just remove the 4 bolts left holding the fender then lift it off.Note: you will likely need to unplug the taillight wires as you lift the fender up so it will come off. You can see the fuel sending unit near the back right hand side. Make sure both wires are plugged in. Preferably, the black wire goes to the connector on the body of the sending unit and the brown wire goes to the connector in the center of the sending unit. Then just reverse the disassembly instructions to put the tractor back together. Edited October 30 by cleat 1 1 Share this post Link to post Share on other sites
WHX?? 48,821 #7 Posted October 31 Jerry may not answer Marty he hasn't been around since 2019 but Cleat has got you more than covered. Don't forget to reconnect the tail light when putting the fender pan back on & be careful not to pinch wires between the fender pan and support. 1 Share this post Link to post Share on other sites
Lee1977 6,663 #8 Posted October 31 I got my 520 H in 2019 It was about half working then, I took it out and cleaned it the best I could. It started working again don't know if it's accurate, but it's working. Share this post Link to post Share on other sites
Marty Taylor 4 #9 Posted November 1 Thanks Lee. I received some detailed instructions from Cleat (in Ontario), which should help me out. Thanks to a Sailor for helping a Marine (1970-1973). Take care. 1 Share this post Link to post Share on other sites
Handy Don 12,232 #10 Posted November 1 (edited) On 10/30/2024 at 10:07 PM, WHX?? said: Jerry may not answer Marty he hasn't been around since 2019 but Cleat has got you more than covered. Don't forget to reconnect the tail light when putting the fender pan back on & be careful not to pinch wires between the fender pan and support. Yep! The fuel sender in the tank uses a variable resistor to measure the deflection of the float and hence the fuel level. Of the many electrical connections on a 520, this one is among the most sensitive to having good, clean connections that don’t add any resistance to the circuit! Edited November 1 by Handy Don Share this post Link to post Share on other sites
