No muffler on it? You can make one and is fairly easy to do.Use pvc 1.5-2" dia x 3-5" long with 2 end caps.Put a hole in ea. cap off center just a little smaller than the tubing.Cut a pc of your venturi tubing about .5" longer than you pipe and poke through the cap so it is about 1" out the top then put it on your pipe,put the other cap on and stick your venturi hose in a few inches and your done.Some put cotton inside but I've found this works well.BTW it can be made from other things that you might have around the house,example... a pill bottle.