1985 Yamaha 5hp steam fixed

Sunfish12

Petty Officer 1st Class
Joined
Feb 6, 2011
Messages
260
Engine was running hot last year, replaced impeller last year, no change. pulled the thermostat, no change.
Started motor today and after one minute steam coming out of telltale. I pulled the thermostat cover and pulled the exhaust plate which is directly behind thermostat cover. The water ports were filled with muck. I started scraping all the ports I found 2 spots that were digging out. I kept digging with a metal coat hanger and 3 hours later I had 2 water ports cleared going around the cylinder. Blasted it out with the garden hose. Put it back together and now it runs cool. Telltail is now pumping alot of water.
 

shewm0

Recruit
Joined
Jun 13, 2011
Messages
1
Re: 1985 Yamaha 5hp steam fixed

Engine was running hot last year, replaced impeller last year, no change. pulled the thermostat, no change.
Started motor today and after one minute steam coming out of telltale. I pulled the thermostat cover and pulled the exhaust plate which is directly behind thermostat cover. The water ports were filled with muck. I started scraping all the ports I found 2 spots that were digging out. I kept digging with a metal coat hanger and 3 hours later I had 2 water ports cleared going around the cylinder. Blasted it out with the garden hose. Put it back together and now it runs cool. Telltail is now pumping alot of water.


got a similar problem with a 2000 yamaha f4 4 stroke, am going to check that
 
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