The OEM vents failed in less than 50hrs.  They allowed gas to splash out covering the tanks.  I tried several options all of which were not viable.  This is what I came up with and it works like a charm.  
You'll need a hand deburring tool to shave a bit off of the openings. I used a shop-vac to keep the shavings from falling into the tank. I took off barely enough to get the threads to catch. I wanted it to be very tight. After I got them tight I made a small hole with a drill bit. It didn't require any seal all or the like. This might be a viable option for other brands as well. Best of luck with your mowers.
	
		
			
		
		
	
			
			You'll need a hand deburring tool to shave a bit off of the openings. I used a shop-vac to keep the shavings from falling into the tank. I took off barely enough to get the threads to catch. I wanted it to be very tight. After I got them tight I made a small hole with a drill bit. It didn't require any seal all or the like. This might be a viable option for other brands as well. Best of luck with your mowers.
 
				