I have a friend whose Rhino shuts down and after setting about an hour
it starts right up,have any of you had this problem before,we think its
vapor locking,any help will be appreciated!Thanks!

 

I am not familar with Rhinos, but deal with vapor locking of trucks and cars.
First, it sounds as if it could be a vapor lock, second is the day time temp HOT? Is he running or using an ethanol fuel? Is he running at altitude?
Alcohol will vaporize at a much lower temp than gas and altitude only increases this vapor.
Alcohol at sea level vapoizes at around 180 degress or so.......at 5000' that temp is lower quite abit.
Solutions for cars or trucks (and the cheapest rememdy) is to add a gallon or so of diesel fuel to hold down the vapors. Some people will use a quart of oil or tranmission fluid to their tank.
My suggestion if you really feel it is a vapor lock is to add a couple quarts of diesel fuel and see if that cures the problem........it will not hurt any thing and more than likly will help clean the system.
This will tell you if it is a vapor lock.

 

The fuel pump system on a Rhino is junk. This is a common problem. Replace it with a good low pressure electric pump and your problems will be over.