"what does this button do?"

Pretty frustrating day today.   Perfect weather; clear and cold.  Ground is frozen, which is great because I'd like to combine a bunch of corn.  

Yesterday I discovered that the fuel gauge on the combine is inoperative.  It reads 3/4 full no matter what the fuel level is, and I discovered that by running the combine out of fuel.  Now that's not a small thing when it comes to diesel equipment -- the take home lesson is that you should never, ever let the fuel run out, but it did, and the combine stopped, and I walked home last night really questioning why I never noticed the fuel level changing.

Someone added this.  the bad handwriting is mine

No matter, up early, with the diesel-out-of-fuel starter kit:  3 cans of starter fluid (ether), a bunch of small wrenches, an air compressor, air line, and a roll of plastic bags and a bag of rags.

I'm not going to go into the first two hours, but at the end the batteries were low, so back to the house, where I got the big battery charger, jumper cables and the gasoline generator to add to the pile of equipment on the back of the truck, and back to the combine I went.

this lever, factory equipment, works just fine.  why mess with it?

It's turning over, but won't sustain.  So I grab a soda and think about it, and decide that it's probably a blocked fuel line.  I detach the fuel line at the bottom of the tank, and sure enough, no flow from the tank.  Blow air into the tank, clear the blockage (make note to myself that I have to empty and clean the tank later) and then notice there's a shutoff valve right there.  And it's halfway "off".  So I open it, and optimistically hope that fixes it.  Back to ether, cranks but no joy.

So I've cleared the line from the tank to the sediment trap, and next I check the line from the sediment trap to the priming fuel pump - a little tiny fuel pump right at the bottom of the fuel tank.  it's fine.  Then I check the line from the priming pump to the main fuel filters (there are two of them), and I have fuel there.  

documentation is something i learned as a software engineer

I'm not going to go into how hard it is to trace these lines through the depths of this machine; everything is painted green, and it's all got dust/mud on it, and it's often behind things.  no  1 hour... two hours...

So then I check the line from the fuel filters to the main fuel pump.  it's good, fuel there.  Then the line from the fuel pump to the injectors.  No fuel.  What?

The fuel line goes behind the engine block, and there's some white and yellow wires going in there too.  I check the manual; nothing there.  What is that?

So I unscrew the fuel line on both ends, and carefully pull it out to find something called a murphy valve (I think that is what it said on it).  A 12v fuel cutoff solenoid.  When its got power it's on, and when it doesn't its off.    I pull it out, apply 12 volts, it works.  I check the wires with the ignition key on and off.  No power.  How did the combine work without power before?

So I look in the cab and find the red box that someone has installed.  And on that red box is a button.  And the red button apparently got pushed at some point, and that turns off the power to this thing, and THAT BUTTON WASTED A WHOLE WORK DAY FOR ME.  ARRGGGHHH!

So I carefully re-install the fuel line, but one of the ends is a bit stripped and won't thread back on, and so I end my day with a trip to the hardware store for a $1.30 replacement part, and I write with a sharpie, carefully, "fuel cutoff solenoid"

And I guess I'll finish that corn tomorrow.