Electronic Accessories,Die Casting Engine Cover,Aluminum High Pressure Die Casting,High-Pressure Die Casting Part Ningbo Zongchi Machinery Technology Co., LTD , https://www.nbdiecastservice.comPump surface and pressure chamber (also known as volute) inner surface of the uneven rust. If the surface roughness, it will pump the pump to reduce water 7% -8%. When repairing, just smooth with steel brush and iron sandpaper or grinding wheel, so that the pump can reduce fuel consumption or power consumption by 9% - 14%.