Drilling out Orifices on Member's Mark BBQ Grill for LP->NG

Last Updated May 20th, 2004 The orifice diameter controls how much gas flow occurs in the HIGH setting (ON in the case of the back burner) and therefore sets the maximum BTU output. If this is too small, your grill won't heat up fast enough and/or be hot enough in general. Make this too big and you will "overrate" your grill - you might not have enough air for clean combustion (yellow flames are bad) and/or other stuff like maybe even melting your grill I guess! ;-)

You will almost certainly need to increase the orifice diameter when converting from LP to NG. On this page, we'll show you how to remove/replace the orifices for the three main burners, one side burner, and one back burner. I'll show pictures of how to do it in that order with comments below.

You should have some idea of "about" the right size to drill out. Be sure to read the notes about this in the LP-NG Conversion Web Page. Notice I said "about" above ... NG has different "heat/burn BTU's", different pressure, and probably other things I'm not even aware of. In my opinion, you want the grill to operate at the same BTU's as before and/or provide the same amount of heat/temperature as before. Again, read the notes in LP-NG Conversion Web Page that talks about this "tuning/tweeking" process.

To state the obvious, it is much easier to drill a hole larger - much more work to make it smaller ... so work your way up to the "right" size.

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Main Burner

Remove the cooking grids & tamers so you just have the burner left.
bbq grill orifices 1


After removing the burner (cotter pin clip on the back) - orifice highlighted
bbq grill orifices 2


Open ended wrenches recommended over channel locks to unscrew orifice - get at from below - comes off easy
bbq grill orifices 3


Here's a closeup - drill 'em out and reverse above procedure. Consider doping the male threads to the orifice. Do three times!
bbq grill orifices 4





Side Burners

Top view of the side burner
bbq grill orifices 5


Bottom view - orifice is highlighted
bbq grill orifices 6


Remove the cotter pin and slide the burner up, forward, and out
bbq grill orifices 7


Now you can unscrew orifice. Consider doping the male threads when you put it back on.
bbq grill orifices 8


Or you could even drill it out in place. Reverse above procedure and you are ready to go.
bbq grill orifices 9





Back Burners

View from the frontside - note 5 screws/nuts
bbq grill orifices a


View from the backside - remove 'em and take off the cover
bbq grill orifices b


Here's the gas line, orifice, and burner
bbq grill orifices c


Spin gas line flare fitting off
bbq grill orifices d


Using wrenches, needle nose pliers, fingers, etc., spin the retaining nut off and the back burner orifice will come right off. I just left the nut in the burner as this made re-attached easier. Drill it out and reverse above procedure. Flare fitting should not require doping.
bbq grill orifices e


Always a good idea to leak-test
bbq grill orifices f