I have a 1973 75 horse that overheats only when idling in a no wake zone
after 5 minutes or so. I replaced the impeller today and the one I pulled
out was in good shape but had 6 vanes. The replacement has 12 vanes. I'm
fairly sure I am supposed to have the 12 in it. Could this have been the
problem? I am going to pull the thermostat out if it still has one. Any
other ideas? Thanks.