Try tightening the small rivet that holds the lever to the board that the contacts are mounted too. Be gentle though as its probably very brittle.
I have a 2026 and upgraded the smoke unit to new liquid smoker. It works great and only took a few minutes to change. The original still worked but I didn't want to deal with the pellets. I bought the kit on DaBay.
Its a great old engine. Your son (and you 
) should get many years of enjoyment out of it.
