The Kubota part number is K5617-31150. You should be able to go on Kubota.com, click on the parts link, and click on the illustrated parts tab to look at a parts break down. Just type in your deck model number!
A little more information may be helpful in diagnosing. Such as, does it start like normal when it does start? Does it smoke at all and what color is the smoke if so? Does it act like its starving for fuel when it shuts off or does it shut off quickly? What does it do when you try to start it...
The issue would not be in your PTO switch if you have it plugged into each other. With the wires plugged into each other you have the tractor thinking that the PTO is always disengaged, therefore it will start with the PTO engaged. The issue is most likely another safety switch. Is your 3400 a...
The piece pictured is part of the feed back control system. Its what lets the control valve know what position the 3pt arms are at. The piece in question should move freely in the lift arm. You can try removing it and cleaning up the arm. Otherwise you should be able to get the part from your...