Guardian RV QuietPact 75D

Welcome;

either the oil level is low, the oil pump may be malfunctioning or the low oil pressure switch is defective

downloadable Manual can be found at
soa.generac.com/manuals/6756411/0D7427

Are you LOW on Diesel fuel ?
Siggy

siggyd777 wrote:
Are you LOW on Diesel fuel ?
Siggy

The reason he is asking is the fuel pickup for the gen is a ways above the bottom of the fuel tank. Around a 1/4 tank, the gen will shutdown to prevent you from running out of fuel and not being able to leave and get more. A year, make and model would also help with correct answers, Welcome to the forum.

I would say if it keeps running when the prime button is pushed you have fuel. Oil pressure sending unit, oil level, high temp sending unit, fuel filter? Is it throwing a code?

LEN

Oil level is low or bad oil sensor.
I've got the QDP75 & have torn into mine a bunch. They are pretty solid and seem to have typical failures that are commonly taken care of with some good Preventive maintenance habits.

The control board is trying to shut the unit down. when you hold pre-heat button down you are by-passing control board and supplying voltage
directly to fuel pump and run solenoid at fuel inj. pump., thus engine continues to run. but holding preheat switch in for too long will overheat and damage glow plugs. As other posters have suggested, you may have bad oil pressure switch, hi water temp switch (although this switch will usually run for few minutes if bad). There is also a overspeed adjustment on control board that can need adjustment. And , finally, if generator is not producing a.c. power, the control board will shut unit down. Possible causes for this are bad field brushes, voltage regulator, or (hopefully not) rotor or stator shorted or open.
And, is generator drive belt driving the generator rotor? This unit has a ribbed belt that drives the generator. There are so many causes for the symptom you have....you need to get a factory service manual, or find a competent service facility. THis generator , as well as all the RV/Mobile generators have been "orphaned" by the manufacturer, but parts are mostly still available.

Wonder if the OP will ever come back and post what was found to be the root cause.