VRO Limit Switch

I have a 1991 Stratos Bass boat with a 150 Evinrude Intruder. The boat / motor is very clean and when I took it out from winter storage I got a No Oil alarm. I have checked all gas, air and oil lines and everything is good. I have removed the small clip that is over the contacts for the alarm module. A small piston that actuates a steel pin in the alarm module is not hitting the contacts. I stood next to the motor and was monitoring engine temperature and would hit this contact every 90 seconds of so. I?m getting plenty of oil and feel that whatever the small piston that actuates a steel pin in the alarm module wasn?t working. I have not checked the diaphragms yet and was looking for some advise if anyone has had this problem before. Does anyone know if you can purchase the outer section of the VRO2 pump?