I have a 1994 40hp Mercury Tracker outboard 4 cyl. It runs fine, but when you get up in the RPM's, the overheat alarm sounds. When I get the RPMs down, the alarm quits. I have been told that I need to replace the Poppet valve, but when I look at various sources for the valve, it does not list one for my engine. I have looked at youtube videos showing replacing them, but can't seem to locate the valve on my engine. Do all outboards have Poppet valves? Thanks for all replies.