Understanding Evinrude water cooling and thermostat - Visualizing the water flow

Understanding how Evinrude watercooling and thermostat work.
This is a 1990's Evinrude 40HP Outboard.
www.marineengine.com/parts/joh...
Camera used:
Sony Alpha a6300 Mirrorless Digital Camera
amzn.to/2uAMYzi
Sony SELP1650 16-50mm Power Zoom Lens
amzn.to/2O7a48S
Sony VCLECU2 12-16 MM,f/2.8 Petal Shaped Fixed Ultra Wide Converter for SEL16F28 and SEL20F28
amzn.to/2mumFGm
Sony E 55-210mm F4.5-6.3 Lens for Sony E-Mount Cameras
amzn.to/2LexScT

[@joseph87328]

thank you, finally someone has answered my question... so essentially the flushing adapter on outboards ( when cold and thermostat closed) only water travels around the cylinders. When open ( hot ) water also travels in the water jackets ...

[@chrisjon9753]

hopefully you still maintain this page. my temp alarm goes off around/above 4k. I pulled the thermostats to remove them and noticed that the old thermostats didn't have a rubber gasket or the metal part for opening flow in the back. I'm worried that the rubber and metal ring dropped down inside the cylinder water passage. I've flushed the engine with salt remove etc a few times. I checked water flow with the thermostat covers removed and one side was strong but the other was a trickle. after several more flushes the flow has improved but it still isn't as strong as the other side. should I be worried about that debris blocking water flow? I'm not sure if the original thermostats had the rubber ring and metal piece or not like the new ones do. they aren't the same color. also the thermostat port on one side of the engine sits lower and this is the one that flows more. the thermostat port on the right hand side of the motor sits up higher and the flow is a lot weaker. should they flow the same? I think it make sense that it would flow less since it sits higher up and would take longer to fill but I'm new to this. any insight would be appreciated. sorry for the book. motor is Johnson 115 60 degree.

[@cenkaetaya]

If you replace the sensor and its still going off that would mean the temps are going above normal, indicating a problem. However if you have a new one and its good you should be fine as the engine is not overheating.
Its always possible something fell down the hole, it could be a totally different problem like something related to pistons or shaft...
Pretty hard to say.

[@chrisjon9753]

@@cenkaetaya thanks for the reply! after looking at a few used cylinder heads i've determined that nothing actually fell. after several vinegar flushes the water flow is pretty even. checked compression just to be sure and that was good as well. i'll test boat tomorrow morning and hopefully i'm good to go. if it over heats again then i will def repalce the sensor.