i posted the ser#6382031 it came back as a 1983 3cyl. 70 hp....well the 83 is original design powerhead?(removable head). & 87 & up, one piece casting powerhead.,(water jacket coverplate only?) this one has the new design powerhead. is this ok? will it work with the 83 exhaust housing & lower unit it is sitting on? its not pumping water & i thought it might need impeller now i dont know.i want to buy but i need these answers.compression 137,139,140& it runs gerat. how do i tell what year & model powerhead?<br /> help please<br /> 