If that's the make you've got, put a 55-in length of exhaust extension on in place of the rain butterfly -it's FSN 4720-595-4146, hose, metal, inter- locked, unpacked. And point it away from the air intakes. FSN 2990-225-4838 gets you a muf- fler from Fed Cat C2990-IL-A-CB6 (Aug 66). When you get it, take off the 55-inch extension and put the muffler on-and put the rain butterfly back. No matter what pedigree rig you've got, but especially if it's a Davey 250 CFM, you'll need a supply of spare innards if you're to work in the field. Washing the Davey's engine air filters in non-sudsy cleanser is fine--but they take 2 days to dry. But wash, change or whatever, those filters are there to protect the insides of your rig. Dirt in the air lines and exhaust soot in your carburetor will make a hangman's noose for sure- and dirt in that aircrammer equals stuck rotors, broken vanes, bent shafts, and an unhappy crew staring right straight at you. NEH>)