seasick said:
Curmudgeon said:
If the water pressure is sufficient, the flush port will get to the same places as the muffs.
:uhm Only if the thermostasts are open ...
This is a common misconception. Even with t-stats closed. water flows to all chambers, just not as much. It has too. If there were no water with the t-stats closed, the temperatures would rise to high levels without the t-stats seeing those temps or the thermo switches either for that mater. Air is a poor conductor of heat.
Without water flow, the vapor turns to steam. The sensors and t-stats take a lot longer to react and are being heated not by the hot coolant but by heat conducted through the motor's internals(mostly metal parts). This is not a good situation.
This is true. Got it straight from Yamaha after being told one day to run off the hose and the next to not run off the hose. Apparently the hose was originally designed for boats left in the water with their motors trimmed up. They also said to run the motors, originally. After a few burnt up impellers they changed the flush procedure and advised to not run the motors. At low rpm the impeller is fine on the garden hose but there is a rpm that could damage the impeller. To keep people from doing this they decided it was easier to just say to not run the engine, but if you ask them about it, they will say it is ok to, just keep the rpms <800 or so. The 15 minutes on the garden hose is sufficient to effectively flush the motor. The 15 minutes is necessary because like he said, it's not a lot of water that flows through the closed thermostat but 15 minutes is plenty of time to get the job done. At the end of the day it's all about what helps you sleep at night. These engines are big investments and you want to feel like you're doing everything you can to maintain them. Old school guys feel better running the motors, they feel it does a better job at flushing the engine. I myself had a hard time believing in not running the motors during the flush, but have been doing it since 2006 and have not had a problem yet. Seasick says he has for 10 years, sounds like it's effective to me.