I own 3 Champions. Two 4000/3500, one purchased in 2008 and the other in 2011. The third is a 3400 remote start inverter I recently purchased. The 2011 had a weak breaker and the 2008 had a frayed pull cord.
To prep for the upcoming hurricane season, I called Champion for replacement parts. I was pleasantly surprised to learn minor replacement parts are free of charge. Furthermore, they provided 4 new breakers, pull cord assemblies and fuel c0cks for both units (I asked for new c0ck filters). He said you might as well replace them all.
You can't beat the service.