genset tripping off

[Rose Mary]

Hi all,
it's a warm sunny day (42 & rising) today so thought I should fire up
the "White Bird" and genset and bring them up to a good temp.
I have had the coach plugged in to 50 amp and had heat on so nothing
would freeze in the weather we've had.
Bird fired right up and is running smoothly as I write this. The genset
didn't want to start, the reset button was tripped. Pushed it in and it
took off and ran smoothly for about a minute. It doesn't seem to matter
if it is on the gen setting (on the switch by the step) or not. It will
start right up, sound fine for about a minute, then trip off.
The water, and oil are fine. It doesn't seem to move the needles on the
galley monitor when it is running and I hurry in to check, after
turning it to the gen position....
When it is on the 50 amp shore the needles are fine.
Thanks for you help, I'll be looking in archives. Mom & I were hoping
to go on a jaunt week after next....grrr...
Rose Mary
82 FC 33