My grill worked for 5+ years and then we had it in
I don't believe a new ignitor will be necessary. But, you may end up having to purchase a new Hose/regulator Assembly. But, before we jump to that, here's what you need to do to troubleshoot and solve the problem. I am assuming, thtat there is adequate gas in the tank(?).
First, it would be a good idea to remove all the burners to clean them and the burner's venturi valve. The Venturi valve is located at or near the burner's open end. It will look like 2-slots cut into the each side of the burner. Spiders love to build nest in them. Since yours has been in storage, it probably has a few spiders. Before you attempt any cleaning of the burners, turn the gas tank valve OFF and disconnect to hose from the tank valve. The reason for this, will become clearer later.
After you have removed and cleaned the burners and venturi valves and reinstalled the burners, do the following:
1. Connect the hose to the gas tank valve.
2. Open the tank valve VERY, VERY SLOWLY (Slow motion, slow).
3. Once the tank valve is fully open, light the burner farthest from the tank first and turn it to HIGH.
Did the burner light and does the flame height look as it should? If so, light the remaining
burners the same way. Now, do all the flame heights look as they should? If so, you solved
the problem (with a little help).
Whenever you turn the gas tank valve OFF. Remember to always turn it back ON Very, Very Slowly.
If the burners did not light and flame heights did not return to normal, you will need to replace the grill's Hose/regulator Assembly, because the regulator is locked up. You can purchase a new Hose/Regulator Assembly for about $30.00 at any home center or hardware store that sell gas grills and accessories. Take you old one with you for comparison purposes.
I hope this helped you troubleshoot and solve the problem. Please let me know and Happy Grilling!!