Really can't tell about the unloader. Can't see other side of pump where an easy start valve would be installed. It looks exactly like mine, which is definitely a trapped unloader because I have hooked two machines together and it doesn't work with a flow unloader or machine with easystart valve. And no, that thread is a regular mpt. Garden hose threads are wider apart. Just look at the pic I posted , or at the end of the garden hose you were using, and compare. Oh and there is no inlet on the unloader,technically the inlet would be where the unloader is attached to pump. You have to take that clear thing off, because if you are plumbing the unloader to the water tank that thing becomes useless. You have to install a filter between the tank feed and the inlet(bottom) fitting on the pump. Once you get rid of that clear thing, you have to buy a 1/2" mpt(thread) X whatever sized barb you plan on using, I have 3/4" ,because I am using 3/4 hose feeding my pump.
That little black hose is your bypass now, it circulates back through your pump when you release the trigger gun. After a while it heats up and destroys your selas. That's why they tell you to press the trigger within two minutes. Bypassing to the tank makes it so the water doesn't recirculate and heat up. Here is plumbing, you can see the Y filter I have between tank and pump. Also you see that he clear thing is GONE. I have two hose feeding my pump, one on each side. Also here is a pic of a garden hose adapter fitting, study the two threads. The top is the garden hose threads and the bottom is what you have now, not the same. It won't matter once you take that clear thing off, because you will be using different threads. The threads on the pump (once you take the clear thing off) are not garden hose threads , you will need a 1/2 inch threaded fitting for that, with a barb the size of the hose you are using.
