So im looking for a DIY guide on how to rewire a double pumper with a hobbs switch installed for the 2nd pump to kick on. I have the rewire kits from STM but nothing is explained for a double pumper...

 

The hobbs switch is the on/off switch for the relay. Have it control the relay coil power or ground (pin 85 or 86).

 

so i have the power wire of the hobbs attached to the relay coil on the relay. but what about the ground wire of the switch?

 

You either hook it up to the battery so that it supplies power to the relay coil, or you ground it so that when it switches it completes the circuit, allowing the relay to turn on. Which way you do it also determines which wire you should attach it to for the relay coil, one is power and the other is ground.


If you hook the hobbs switch to power, then you ground the other relay coil wire. If you hook the hobbs switch to ground, then you hook the other relay coil wire to power.

 

Does the hobbs switch send power to the second pump? Or does it merely trigger the second pump? If so, do you have to add in a second relay for the second pump?

 

I’m buying a Buschur double pumper with twin walbro 450s. I don’t have Hobbs switch setup. Is it needed? Or Can I just drop it in replacing my existing aem 320 pump/housing?

 

I have a hobb switch on my bosch 044, and works like a charm. My bosch only kicks in at 7psi

 

You will have to wire up a new circuit for the double pumper, there are many threads on this topic if you do some searching.

 

So all the wires be a 10 or 12 Gauge wires?