What would cause fuel to get in oil on gen rac generator?

You didn't indicate the age of the unit, hence the oil consumption which can be under heavy hot laod, I believe they are two different issues. With the motor home sat not on shore power, and the gen off measure the battery voltage at the generator battery wire, it may read around 12V start the generator and re-measure it should jump to around 13.8V if it does then the gen battery charger system is intact, which then you need to check vehicle battery converter is working. If you don't have 13.8V then the cause is most likely a stator battery winding, or rectifier.

These type of gens have a low oil shutoff. Check the oil. Always have spare spark plugs, a cheap fix. My gen always wanted a new plug every year. Look to see if it has a fuel filter.

Seems that you have covered all the bases. The problem that you describe could be related to fuel lock or restriction in the fuel delivery system. Easy to check. Remove the air filter and have carb cleaner ready. If you are near the gen when it begins to quit, spray just a little carb cleaner to see if engine tries to run. If engine begins to run or continues to run with carb cleaner, then suspect fuel delivery problem. If the engine seems to stop quicker with carb cleaner, suspect flooding caused by too much fuel pressure (fuel pushed past the needle due to pressure in the tank; open fuel cap and listen for air pressure release). Fuel delivery problems are caused by collapsed fuel line, restriction in the fuel cut-off valve, restriction at the fuel filter (use larger automotive type), negative pressure in tank caused by no vent at cap. Rare problem with fuel delivery is caused by sudden heat rise at the carb causing fuel to boil out of carb. This is caused by the engine running very hot, lack of air across cooling ribs caused by debris or fan missing blades. You can eliminate the complete fuel delivery system by mounting a small fuel tank on a stand and running fuel line directly to the carb for test. The tank needs to be higher than the carb so that you will have good gravity feed. Good luck

As you describe the problem, the reason is unstable load handling.
This means that the fuel or air is not enough.

When begin to be unsteady:

1. If smoke comes out of muffler - the input air is not sufficient. Try to clean or change air filter (cleaner).
2. If no smoke, the fuel is not enough. The reason may be the mechanical governor, or the fuel supply to it, fuel filter/strainer etc.

Check for intermittent oil pressure switch. Monitor the possibility of low oil pressure shutdown.

There's a oil level sensor on that gen,if it doesn't "see" enough oil it grounds out the ignition.This is to keep you from destroying the engine due to no oil.If that's not it re-post and we'll try something else?

its seising up ,the oil is not getting round properly,blow out all pipes with a compresser,or its over fueling

A broken ground wire on the alternator ( generator ) would cause it to not charge , and could also make the light not work.

All generators need to be run once a month. All things from the tank to the and including the carb will get gummed up with dried out fuel. I have a whole house generator and a 5500 watt gen set on my motor home. I keep fresh fuel in the stand alone house generator in California in case of a bad earthquake. I drain the gas after every run and keep all vehicles full of fuel just in case. Run gen sets at least once a month or pay pay pay!!

i have had my generator for 6 years. i use fuel stabilizer and do as you did in shutting it down. I do not drain my fuel but it doesnt hurt. I would question putting anything in the engine that could in time cause problems. I use synthetic oil, this should coat all internal parts well enough to not need extra oil. I do start the engine a few times a year and let it run 5 mins. or so. I live in SW La so having a generator that doesnt work during hurricane season is not a good idea. The steps you are taking should keep your engine fine. It is a good idea to run it and use the power every now and then. This keeps the magnets in the generator in good shape.