Hello i have a B2150HST it starts up with alittle black smoke then runs fine.When i try to move forward up hill it loses power let off revs back up fine but try again boggs down--if go reverse it seems alot better but not the power it once had. I have just taked off tank tank full of rust waiting for the restorer to clean and coat tank before i put it back on.Am i missing something?? Thx for any input Mike