Adding a gas/fuel gauge

[meadowfield 2,651]

as I just did it and included on my C-121 build thread, I thought I would give a little more detail here on adding a gas gauge to a 1978-1983 C series. It might work on 300/400/500 but I don't know what the gas tank is like.

 

Start with a universal sender and Gauge. 

 

 

Then cut a 1-1/2 hole in the right side of the tank. Marking holes to use self tapping screws to seal the sender. (yes I ended up a little off centre...  hard to tell with sender unit in place)

 

 

adjust the height and cut the dip rod down to just reach the top and bottom - about 7"

 

 

Screw unit in

 

 

connect +/- to battery and sender to remaining terminal - making sure sender is grounded at the tank end.
 

 

 

and there you go

 

A little easier and snazzier than getting off to see the faded/obscured gas gauge that is on the filler cap.

 

 

 

 

Edited June 29, 2020 by meadowfield

[Blackhood Bill 721]

@meadowfield that’s very cool. Would like to see more pictures with wiring connected. I think that would be worth a try on a 300/400/500 series. I’m slowly in process of redoing a gt1848 and may just try that.

[Stormin 9,983]

 Neat, Mark. May just do that. Only got one decent cap gauge between three tractors and a stick for the Sears/Roper.

 

 Where did you find them?

Edited June 29, 2020 by Stormin

[meadowfield 2,651]

24 minutes ago, Stormin said:

 Neat, Mark. May just do that. Only got one decent cap gauge between three tractors and a stick for the Sears/Roper.

 

 Where did you find them?

ebay for gauge, £12.99 from the UK 

[pfrederi 18,339]

 Do they have some sort of dampener for the gauge?  Bouncing around on a rough lawn that gas is sloshing a lot in the tank

[Stormin 9,983]

  Be no different to any vehicle driving off road. Just look when your on flat, level ground.

[cleat 7,032]

This is a pic of a factory sender unit installed in a 520. I also just put a 520 tank and gauge into a 312.

 

 

I wonder if your sender unit has the same resistance values for full VS empty because these 520 senders are getting hard to find in good working order but the fuel tanks themselves are plentiful.

 

I also wonder if the mounting hole and screw holes are the same.

 

One more thing, some of my 520's have damped fuel gauges and some don't so they come both ways (must be dependent on year I guess).

 

I look at my fuel gauge all the time and that is why I added one to my 312. It is a useful upgrade.

 

[1995 520H+96+97 937]

I used this one the 1995 520H. It was already clocked correctly, screw holes lined up, Reused original screws. Had to cut off 4" of float arm. Ground off the positive terminal so it wouldn't touch the fender pan.

 

 

[cleat 7,032]

I see most universal sending units are 240 ohms empty and 33 ohms full.

 

I will need to verify that this is what the SW fuel gauges in my 520's want as well.

 

I don't need a sender right now but it is good to know there is an aftermarket source available.

 

Thanks, Cleat

[cleat 7,032]

 I just went out and tried to get measurements of my spare somewhat flaky sender units.

What I came up with is around 270 ohms empty and 35 ohms full.

 

I also took some pictures of a unit and measured it as well.

 

 

 

 

[meadowfield 2,651]

6 hours ago, cleat said:

This is a pic of a factory sender unit installed in a 520. I also just put a 520 tank and gauge into a 312.

 

 

I wonder if your sender unit has the same resistance values for full VS empty because these 520 senders are getting hard to find in good working order but the fuel tanks themselves are plentiful.

 

I also wonder if the mounting hole and screw holes are the same.

 

One more thing, some of my 520's have damped fuel gauges and some don't so they come both ways (must be dependent on year I guess).

 

I look at my fuel gauge all the time and that is why I added one to my 312. It is a useful upgrade.

 

 

wow!  how cool is that - I never saw how it was done on a 520, but wanted similar!  seems theres really only way of doing it! 

 

[BrianX128 107]

I ordered one of these this week as I want to try this on one of my C series mowers, how difficult is it to get the metal off to access the tank is it just the seat and some bolts under there or is the foot rest area and belt guards bolted to everything also? I can't remember.

[BrianX128 107]

Just did mine, works great. Just gotta find my tool I used to cut holes in the plate by my voltage / rpm gauges where you have your plate on my C141, though I better get one for my wife's mower too lol..

 

[BrianX128 107]

 

That's better! Only issue I ran into was the seal for the sending unit doesn't really seal. The bolt holes will weep when the tank is full. I jb welded the entire top of the sender from the sender wire outside to the plastic of the tank and its leak free. 

 

Not sure where I'll put the gauge on the wifes mower since it's a 417a and has the hour meter and volt meter already.