Iím having an issue with my starboard side motor losing oil pressure, and Iím looking for a diagnosis from the resident experts. Here are the symptoms.
At the beginning of the summer the starboard side motor would start losing oil pressure after 15-20 minutes of running time. We thought it was a gage problem so I replaced the sending unit as well as changed the oil. After that everything was fine. Fast forward to now.
The oil has 25 hours on it and Iím seeing the same drop in pressure that I was seeing at the beginning of the summer. Hoping it might be the sending unit again we put a mechanical gage on the motor, but experienced the same pressure drop. Both motors generally run between 45-60 PSI depending on how hard Iíve been running. Now after 15 minutes of running time the starboard side oil pressure will completely fall off from 50 PSI to just under 20 PSI. Itís not a gradual decrease either it just drops. Now if I let the boat sit for 10 minutes and fire it back up the pressure will go back to normal for another 5 minutes or so. The oil temp for the starboard side is now consistently 25 to 30 degrees higher then the port side. Iím currently running twin 350s with Prochargers. Iím using Valvoline 50 weight oil. Any thoughts?? I donít run the boat hard, and I canít imagine the oil breaking down after just 25 hours? I plan on pulling the motor this winter. Where should I start? Thanks.