I own two Craftsman mowers one with the B&S 6.75 HP Quantum Series engine and the other has the B&S 6.5HP Quantum Series. Both engines are practically identical or so I thought as I was removing last years spark plugs and beginning to install new RJ19LM plugs I noticed the 6.75 has a difference plug...RJ19HX?. Went back to the auto parts store where I purchased my plugs from and they didn't have any in stock, in fact wasn't listed in the computer either and the guy never heard of that particular plug. Checked a few more stores same thing, the only place I could get it from was back at Sears after calling. Upon comparing the two plugs they look identical, does anybody know if I could get away with just putting in an RJ19LM plug instead?
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