ive got a 60 75hp johnson the upper id tag reads model #v4sl-12s witch im sure is a 1960 75 hp im not sure if its a longshaft or not its eletric start though and im sure its magneto ign i pulled the battery cable while it was running with the alt/gen unhooked it stayed running strong the bottom id tags read model # vxl-12r i looked this up and its a 60hp (1966?) the reason im wrighting this is when the motor (60 75hp) is ildeing in neutral it seems to run, rev and idle fine but when i put it into gear it runs fine until about half throtle then it just dosent seem to have the power it should it will only do abought 20mph on the 1960 16" glaspar it came on i think now ive tryed adjusting the carbs no diffrence i know probly not but could it be a 75hp motor on a 60hp drive unit (bottom end) and that the thing cant rev like its supposed too also could the prop be the wrong size any body know what size prop it should run i dont have a manual so i cant do the points and im almost sure its in the timing anybody have any suggestions or tips on setting the points thanks for all your time and patience
