Nexgrill 720-series main burners are usually stamped tubes that slide onto brass valve orifices at the front and pin at the rear. They rust when tents fail. They also slide off the orifices when the cart is dragged by the lid or when a pin walks out. Both look like a dead grill.
Not affiliated with Nexgrill Industries.
Shop with the 720 number, not “4-burner”
- Count main tubes. Ignore the side burner.
- Measure length and look at the inlet.
- Photograph the rear pin or screw.
- Search Amazon or BBQGuys for Nexgrill 720-0830H burner (or your exact stamp). Compare the photo to the tube in your hand.
- “Universal 4-burner” kits that are 3/4 inch short will not swallow the orifice and pin at the same time. That gap is a flashback.
- If the tents are lace, order heat plates in the same session.
Safety
- Tank off and removed. Box cold.
- Do not enlarge orifices. Do not pry a stuck tube so hard you bend the brass.
- Lid open when you test. Flashback (flame at the shutter or inside the tube) → shut the knob and reseat.
Procedure
- Photograph tubes, pins, electrode, and any carryover notches or crossover. 720 carts vary; your photo is the assembly manual.
- Grates and tents out. Move the electrode if it blocks the left tube — pull the lead at the module, do not snap the ceramic.
- Straighten the cotter pins and pull them. Keep one as a pattern. Have spares.
- Lift the rear of each tube and slide the inlet off the orifice. If rust-welded, twist the tube, do not lever the valve.
- Hold old tubes to the sky. Extra pinholes, split seams, crumbled inlets: scrap. A packed dauber nest you cannot extract whole means that tube is scrap even if the top looks fine.
- Dry-fit the new set one at a time. Inlet must fully swallow the brass. Pin hole must line up without stretching. If the hole lands a half inch back, stop — wrong kit.
- Pin the rears. Bend the cotter enough that vibration will not walk it out.
- Refit the electrode and set a nickel gap. Seat tents over the port rows.
- Tank on slowly. Soap-and-water the tank coupling. Lid open. Light each main, then the side burner. Even blue rows. A roaring jet at the front shutter is a tube not on the orifice — shut down, reseat.
After the first heat cycle
- Look at the pins again. Stamped tubes expand and walk.
- If a new tube rusts through in one season, the tent above it is missing, short, or lace. Fix the tent, not the tube, the second time.
Stack math
- A full 5-burner refresh on a 720-0896 — tubes, tents, igniter, tray — can meet or exceed a new cart of the same class. Look up current totals. See repair versus replace.