My u17 mini excavator runs great for 30 to 45 minutes then gradually starts getting hot.  Eventually it gets really hot and if I run it too long the small water filler tank is boiling when I turn off the machine.  The machine runs great and seems to have good power.  Also, there is no discoloration in the exhaust
	
		
			
		
		
	
								 
				 
				
		 
 
		