If it has a glow plug it'll be in the intake manifold. You should be able to see it as it has a wire running to glow plug from the starter switch. The switch should have a position to send power to the glow plug. My 2610 has it marked on the legend. If it has a freeze plug heater you should be able to find the end of the 120 volt male plug.
I use an external tank heater. Warms the engine well.
rcmjr.
