Hello,<br /><br />Help!<br /><br />I completely rebuilt my BF100 mid eighties 10HP Honda. It runs beautifully, except that the water flow is poor. <br /><br />Here is what I know:<br /><br />1) The impeller is new and installed correctly.<br />2) The water pump is in good repair and has new gaskets.<br />3) The water pump housing (lower end unit) is prestine.<br />4) The water tube is unclogged and clean.<br />5) All the hoses are unclogged and clean.<br />6) The cooling passages within the piston block and valve block are clear. <br />7) The water flow is good when the lower supply hose (based on the oil fill housing) is disconnected suggesting the impellar and water tube are in good working order. Once connected the flow becomes very poor and water just spits out of the top of the hose where it connects to the thermostat housing. <br />8) The thermostat housing is clear and the thermostat tests fine. <br /><br />What I have discovered is a hair line crack situated on the outside of the piston block, right where one of the head gasket bolts are situated. On the inside of the block, where the crack is, is where the water would channel through to cool the pistons. I discovered the crack when pressured air was pumped through the system and noticed water spitting out, it is a very fine crack. <br /><br />The question is - would a very fine crack in the piston block effect the vacuum created by the water pump and impede water flow?<br /><br />Thanks.
