I was looking into why Yamaha 40hp C40 would not idle the other day in cold water, 50F, when the last 2 summers it was running good. This was the first time I tried to run it in Dec. Thinking it was related to the water temp I was checking the thermostat and pressure relief valve. When I pulled out the plastic relive valve plunger there was a very small spring laying on top of it, yes it was just setting there. The spring was approximately 1/16" in diameter and about 5/16" long. I'm not by the motor now so I can't post a pic of it but will get one soon. Any ideas what this small spring is from, or is it something the pump picked up and passed along?
By the way the thermostat was closed but the pressure valve grommet was deformed a bit, I'm replacing both.
By the way the thermostat was closed but the pressure valve grommet was deformed a bit, I'm replacing both.