Need to check your impulse grommet to make sure good.    Good time to check the little rubber intake boot too. 
Page 3 in IPL http://s30387.gridserver.com/partsDiagrams/Husqvarna 51 and 55.pdf
	
		
			
		
		
	
				
			Page 3 in IPL http://s30387.gridserver.com/partsDiagrams/Husqvarna 51 and 55.pdf
 
 
		 
 
		