New to working on tractor.   What is the purpose of two oil fill ports on the valve cover and a third on the assesory cover on my YM 1600?  I figured they must use this valve cover for other applications so I change the oil today using the fill port on the assessory cover, then cleaned the tractor.  When I started it, I found an oil leak from my valve cover gasket, and it was definitely not fresh oil. Is it just a couple ounces of old oil that didn't drain out of the valve cover, or is there another oil reservoir I need to attend to?
	
		
			
		
		
	
				
			 
 
		 
					
				 
						
					