Re: Evinrude 225hp V6
Those look like the original T-stats that were in my 1988 225's. The new ones are black. They look a little different but as long as you order for the correct HP and model, you will be OK. I would just replace the whole thermostat. One of mine failed when the threaded portion broke away from the main part of the thermostat. I would guess all the heat cycles caused the material to fatigue. In any case, you don't save much by replacing the vernatherm and spring.
I see Faztbullet responded to your other thread regarding proper temps and water flow at idle. He knows these engine inside and out, so you can bank on what he's telling you.
Let motor idle for 10 minutes to warm up for a compression test. In the mean time I checked the temperature of the water coming out of the pee hole, it was 128 degrees. Also checked the heads around each spark plug and was getting temps of 151 to 169 degrees. Removed the thermostats and the stbd stat seemed like very little water had gotten to it. The port stat had plenty. I left the stats out and fired up the engine to check water flow. Was getting a decent amount of port side but not as good on stbd but was getting water. I want to go ahead and replace the stats, they are the plastic type that actually screw into the gasket, then there is an o ring inside the housing. Have never seen thermostats of this kind. Anybody have any ideas on this? Any thermostats I've looked at online to order just don't look like they would fit. This engine is supposed to be a 1988 Evinrude 225.