Small Engines (Lawn Mowers, etc.): outboard over heating, head gasket, water passage

Question
Hi, I have an older about 1975 20 hp Chysler outboard. It ran fine for years,but now started to overheat. I replaced the impeller, but it still over heats. It is Model H202. Could it be the head gasket, would that cause it to overheat. I have taken it apart, and all passages seem to be clear. their is no thermostat.  any ideals? Thanks Bob

Answer
BOB, HAVE YOU AN AIR COMPRESSOR?  YOU MAY NEED ONE.  WHAT I WOULD DO BEFORE I PULLED THE HEAD IS DROP THE LOWER LEG ONE MORE TIME AND BLOW SOME AIR DOWN THRU THE MOTOR FOOT WATER PASSAGE AND THEN UP THRU THE MOTOR LEG WATER PASSAGE.  IF POSSIBLE SQUIRT A LITTLE WATER UP THE TUBE AND THE GIVE IT A SHOT OF AIR MAYBE YOU CAN BREAK LOSE WHATEVER IS STOPPING UP THE PASSAGES.  THIS CAN BE A REAL HAIR PULLING PROBLEM.
I HAD A 3 HORSE DRIVE DAMN NEAR NUTS.
GOOD LUCK, IT'S FISHIN TIME
GEORGE