No, one has a j at the end and the other has a y.
Champion - RDJ7JNGK RDJ7J
RDJ7Y Champion
E3.16 or champion RDJ7J
Champion RDJ7Y is the correct number.
This part number is for a Champion RDJ7Y spark plug. Set gap at 0.025" I bought a replacement plug, DJ7Y, at Home Depot on 10/6/13 for $2.38 + tax. The DJ7Y replaces the RDJ7Y. This plug is used for other tools such as my Ryobi trimmer and McCulloch chain saw.
I am using a Champion 872 RDJ7Y to replace the Jenn Feng 9111-310002 that was OE in my chain saw and it works fine.
Two compatible spark plugs for a Troybilt weed whacker that currently has a spark plug with a model number of 794 00055 is the Champion E3.16 or the Champion Spark plug RDJ7J. Both of these spark plugs will give your weed whacker the starting power needed in a replacement. You can buy them here http://www.mymowerparts.com/partdetail/1060/1042/10783.php
it uses a RDJ7Y
According to Champion, the correct gap varies depending upon the application. Most applications show an OEM gap of .025" but a few had an OEM gap of .030". I would set it slightly on the wide side of .025", and it will be good enough.
it uses a RDJ7Y
Champion Spark Plug Co. is currently owned by Federal-Mogul.
the R stands for Resistor. It is a resistor plug.