Generator vapor locking

So I've been trying to track down this issue I have been having with my 5500 Cummings/Onan generator. It will die out intermittently. I finally tracked it down to it dies when you hit a very rough highway or harsh jolt from a dip on a bridge expansion joint. And I diagnosed it even further in that it does it only when hot outside 85+ degrees. I found that if you give the generator a good push/shake it will want to die or will die. It doesn't do it when it 85 or less. It has a complete tune up, filters, oil plugs etc. I'm going to clean the carb and maybe decaf in it. It has 370 hours on it. But it's not a runny no idling problem. I believe the gas in the carb is boiling and when it gets shaken hard it sucks the air from the boiling gas.
Has anyone run into this. I was going to install some type of vent on the outside generator door, but when I open the compartment it's not hot. When I open up the generator cover you can really feel the heat, which is why I'm think the fuel is boiling when it's hot outside. The generator will run with no issues when it's below 80, it never dies then!
I have an outdoor thermometer in one of my compartments for outside use. I have seen storage compartment temps over 110 degrees. My gen is at the LR so it's getting all the heat sucked into it instead of cooler air.

Anyone?