Stainless Steel counter sunk screw for the Blower Wheel  Cover the M6 x 40 are  located at the bottom of the housing and 2 are required per engine. The bottom screws are longer than the top screws as the fuel and the engine breather overflow pipe brackets fix to these screws. We do sell a Kit of all 4 of the Blower Wheel Screws Part No 1912/1/1