Generac 5500XL shutting down after about 20 minutes

[JohnCarter]

Had a major storm a week ago (Friday evening, 9 July). 60+mph winds took out a lot of trees and power lines (subdivision has underground power, but the feed from the substation is aerial).

Not being too concerned about the fridge or freezer (they keep OK for 12+ hours if closed), I didn't get out a generator until Saturday morning - about the time I started using the chainsaw ;-)

The Generac started OK and took the load of the fridge and freezer. Maybe 20 minutes later, I noticed the gen had stopped (when I stopped the chainsaw to move some cut wood). I checked gas and oil levels and both were OK and the gen started back up on the first pull - then stopped again a short time later. I'm not sure how long it ran either time as I wasn't standing there watching it run - more like 30 feet away clearing limbs from the driveway ;-(

We were still OK on power. When time permitted, I started the old Coleman 1850 which can run the fridge (but can't manage the freezer, even as the only load). Power was restored around noon - we were in the last 300 restored of the original 10000+ without power.

My usual test run is a 1500-2000 watt load for 10-15 minutes, so something that could affect a longer run wouldn't have been caught on a test run. The gas cap was replaced about 6 months ago, so I wouldn't consider it high on the suspect list. The outside temperature was about 85 degrees.

I'll probably get the gen out Saturday and see how long it runs - and be checking the oil pressure light.

Other suggestions welcome.

Generator details:

Model 09778-4
5500XL
S/N 4395922
V 120 / 240
A 45.8 / 22.9
W 5500

Engine:

GN-320
OHVI
11HP

320
98117 17

EHD A1453B
92217

Thanks,
John