Engine speed

[Hinomotoman]

Is this a gravity feed fuel system?

Check the vent on the filler cap.

It has an electric fuel pump.

 

[Hinomotoman]

IF it was DRY.. it means no fuel is being injected into or thru the injector..
I suspect the injection pump.. you say the "back cylinder".. so it will be easy to remove the steel line ON THE PUMP to SEE if fuel is coming out of it..
Do yourself a BIG FAVOR & use the double wrench method.. hold the pump "nut" while loosening the line nut.. or you stand a chance in loosening the pump [delivery valve holder] nut before the line comes loose..[not good]
You can do the same for another cylinder ON THE PUMP to compare the fuel delivery. [squirts]

It was dry. I soaked it in carburetor cleaner and it's working now. I had already loosened the fuel lines from the injector pump. Fuel pours out of the tops of the injectors. All injectors are working now. When I loosen the fuel line on the tops, the engine slows down on all 3. With the mid PTO on, it slows down more than with it off. (naturally).