head height is about 4' - although that wont matter when comparing the same condition to a weaker pump  
 
I would expect some loss with the 3/4" line, but not 600 gph loss  
I'll try changing the intake to a straight run.  
 
the only other thing I can think of - is the motor is going - is there a way to inspect, or test? 
 
I would think with the motor, it would either work - or not work 
		
	
		
		
		
		
		
	
		
		
	
	
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