Exhaust pressure valve

[vilord]

I have one of these:

in my boat, and while waiting for the new exhaust gasket to come in, I started pulling out the old one, which necessitates pulling the muffler.
In the process I slipped and managed to unhook the spring on the valve above. Out popped the spring and a metal ring.

It is pretty obvious that the spring goes back on top of the valve under the red adjuster, but what is the metal ring for? It seems to be about the size of the valve inside (2 inch diameter or so), but it is a split ring so it won't stay on the valve, it just falls underneath.

Any ideas? I checked the manual and it didn't even mention the valve, only showed the hole where it pushes in.

 

[kustomkarl]

This is a Water Flow Regulator Valve,Here is some information on it . If you looking for a breakdown goto the "parts" link and see what comes up.

The water flow regulator has been calibrated at the factory and should not be tampered with or modified in any way.
CAUTION: Strictly adhere to the calibration procedure or otherwise serious engine damage will occur.
If engine does not maintain RPM or the engine is experiencing poor performance, the water flow regulator valve might be out of adjustment. The normal adjustment as done at the factory is as follows: On the top of the water flow regulator valve locate the red plastic adjustment screw. Mark the location of the screw with a dab of paint for reference. Turn the screw clockwise (tighten) until the top edge of the screw is flush with the top of the black cap. Turn the screw 2 clicks counterclockwise (loosen). This is the factory spring setting. The bottom tapered screw should be screwed in just snug.

This Regulator valve plays an important part in cooling the engine. Each fitting is a special size and controls the flow of water to the different part of the engine depending on the rpm. Never mix up the fittings or you'll have problems with over heating and maybe seizure.

I hope this helps.

Karl