Join Date: Nov 2009
Location: georgia's toe-nails of the foot hills
Re: Craftsman LT2000/Kohler 17 is Blower Fan Duct needed? Have one for sale?
That guide helps flow cooler air into the blower housing. Without the guide, heated air from under the cylinder can get re-circulated back into the cooling inlet, and produce a hotter running engine. The notable symptom with todays 'fuels' is that the engine may suffer from percolation of the fuel, and what was called 'vapor lock' back in the day. If your fuel crosses from one side to the other to feed the carburetor, and uses a metal line passed through the blower housing, you may suffer the percolation/vapor lock without the shroud. I think it was called 'turbo cooling' by Sears when the products were new. There are several varieties of shroud, some being taller, and others having the 'tray' that extends rearward from the engine.
Is it absolutely necessary? No. I doubt that it has a lot of effect on engine temperature, though I expect it would drop the running temperature to some degree. In my case, with no 'factory' shroud, I experience vapor lock on hot days, and can avoid the symptoms and problem by removing the hood, allowing free intake of air. With the hood on, the engine seems to experience erratic misfire. Not a 'complete' miss, but more of a stumble.
I think a substitute could be made from readily available materials, such as plastic or sheet metal. Given the unavailability of the part(as built), the only option beyond making my own, is to find one from a model year one or two years newer when they were factory installed. As I see it, I need a partial circle that is open to the rear, and come close to the underside of the hood. I could add some 'rubber' gasketry, or foam rubber at the top to make a better seal on the bottom of the hood sheet metal.
simplificate & add lightness
It's not how hard you work, it's how much you get done.