Ford 1700 Diesel Tractor Won't Start

[HotHunt]

I have a Ford 1700 diesel tractor that will crank but won't start. My neighbor told me that he thought the "fuel solenoid" was bad. He showed me where it was at and said it costs about $120 to purchase a new one. Before I buy a new part for that much, I want to verify what the part is. I've attached a picture with the part circled in red.

Can anyone please help me? What is the correct part name and what does it do? Thanks.

[rdbigfarmboy]

Take the two lines going from the injector pump up to the injectors loose. Spin the tractor engine and see what comes out.
You probably have something blocking diesel flow. Does the diesel freely flow thru the clear plastic filter?

[HotHunt]

Thanks for your response. The fuel is moving through the lines okay and there appears to be no blockage. The diesel flows through the fuel filter with no problem or residue in it.

But my original question was "what is the part I have circled in red on the photo that sits to the left of the two fuel lines lines"? What part does it play in the fuel system? How can I tell if it is a problem and needs replacing?

Thanks for any help you can give me.

[rdbigfarmboy]

So are you saving fuel is delivered to the injectors, that it is beign pushed thru the injector pump and to the injectors. If fuel is getting to the injectors then what ever it is is not affecting fuel delivery.
question
When the tractor was running how do you turn it off stop the motor?

Ive never seen a 1700 ford or suzi or mitsu so I dont know the engine but most all tractors have similiar parts with similiar functions.