yamaha 1999 150 water pressure control

[wolffman]

I purchased a yamaha 150 1999 model. took the valve pressure control apart to imspect and the plastic valve was stuck. cleaned housing and noticed there was not a rubber grommet. part number 90480-20m050-00. I have one to put back in and not sure if grommet just sits in the hole or if it cradles the rim in the housing. no experience with yamaha and have no reference. thanks in advance.

[amahaork]

cradles. don't loose it inside, may be old one inside already? replace valve for mushroom style