I had 2 Lancasters this week that the leaf blower was the only tool that would clear the exhaust path. Both customers complained of a dirty burn, shutting down w/#2 flash. I checked them and both were only pulling a .1. I cleaned them both completely. Pulled comb. fans brushed up the ash traps ect. Only got maybe 1/4 point increase. I had everything as clean as it could be with a shop vac. Then I hooked up leaf blower, Ran it for maybe 30 sec. w/ door open and vac switch unhooked. Checked draft, right back up to .3!There are places in the older St Croix that you can not get to!! A clean St Croix should pull about .3 w/ near wide open intake air shutter. Hope this info helps someone else