How to prevent generator vapor lock

I have a Onan Gold 7000 generator. Runs fine normally, but sometimes when traveling in hot weather it develops vapor lock. When it happens, it has been when temperatures outside are above 97/98. We hate to travel when it is that hot, but sometimes crossing Texas in June/July, it's unavoidable. When it's that hot it is also a time that you really need the a/c working well, and if the generator develops vapor lock, then no a/c and it's a miserable situation. I'd like some ideas on how to avoid this situation for this upcoming summer. Thanks.

Onan is installed in a Itasca Suncruiser Motorhome