In the almost nine years we have had our PC we have never experienced a problem with our generator. I prime it in the 3-5 second range, closer to 5 if it has been stored for thirty days or so and it always starts easily. Once every month is "PC Exercise Day". Our storage facility is three miles from our house and I look forward to a pretty day in the winter to go out there, fire up the Ford and start the generator. I drive up the road about 25 miles and come back to the storage building so a trip of about fifty miles. Since I often stop for coffee after the 25 miles (or lunch), I leave the generator running while I am inside. I believe that monthly exercise keeps her going and I KNOW I enjoy that couple of hours every month just thinking about our next trip.
Here in Central Oklahoma, we always have several nice days during the winter months to allow such a schedule. Last week, it was down to single digits a few nights, snow and a couple of days not getting above freezing and this week we are seeing Sixties for highs for three or four days and not a cloud in the skies. Pretty typical for winter in this area.
We spend several weeks every summer in the Southern Rockies to get out of the heat and our favorite camping area is at 8000 feet or so altitude. I do adjust the carb setting for a higher altitude and am mindful of the significant loss of power output at altitude.
Like someone else said, if the generator has been operated in the last day or two, I don't prime it to start it (most times).
I really like to start the Ford up prior to firing up the generator so I am not giving the coach batteries such a whamo after they have been sitting for thirty days during my Exercise Day.
Paul