Also, check the water
flow. I have a Yamaha 8HP which has a chronic but very insignificant flow problem...if you watch for it. When you start the engine
, you should see a pretty strong "pee" stream from under the engine
on the starboard side. If you don't see it, or if it's only a trickle, then use a small wire or other device (I use a thinned plastic wire tie) and stick it up in the little hole. There's a small metal tube extending just a bit below the bottom of the engine, behind the gear
lever. That should start an immediate strong flow.
I check mine every time I start the engine, and it's amazing how often the flow needs some "help". FloMax for outboards????