Thermostat

Would you verify that it is a "75D"?
That is an awful big genset for a MH. Get model number off unit. Should be more like a 7.5, not a 75 which uses a John Deere power unit.
I believe you have something like this:
Generac 5860

Check the GENERAC website. Might be able to get it there. If not, google the part number. It's in the owners manual (at least it is with my 5.5). Then google the number. Someone has it.

g'luck !

Is this the model qp75D?
This could be thermostat.
thermostat

This is a model #:004270-3 Quiet pact 75D

Manual on page 12 gives thermostat number. It maybe available at some auto parts stores such as NAPA.
Manual