You mentioned the MH had been sitting for sometime. I would bet the carb needs to been rebuilt/cleaned. Modern ethonal fuel is horible on engines that do not run regularly. the init is old enough, that the califonia carb rules i dont think were in effect so you should be able to pull the carb and clean it. If you can try to run ethonal free gas. Especially in the fall before putting it away for the winter. Also start the Gen set at least once a month.