Just make absolutely sure you don't overfill the fuel tank on the Hobart or the carb. can flood and cause the rings not to seat. Not covered by warranty. The Champion is most likely the same as a Miller Bobcat.
Non vented fuel cap and the fuel runs back down the vent line instead of venting or something along those lines. It happened on my friends Lincoln and the shop had 8 other's that had the same problem.