PlayDate
Well-Known Member
Although Westerbeke has not released a Service Bulletin on the subject, a number of Westerbeke owners are experiencing a problem that it almost impossible to diagnose. The problem turns out to be the oil pressure switch part number (Westerbeke): 37323.
Symptoms:
Generator starts, runs and randomly shuts down with or without a load after the engine has warmed up. What appears to be a fuel problem is actually the oil pressure switch opening which triggers the control board to shut the engine down. For clarity, there are two oil pressure switches on most Westerbeke generators. Switch "A" (37323) is normally OPEN and closes when the engine starts and oil pressure keeps it closed. Switch "B" is normally CLOSED and opens when the engine starts and oil pressure keeps it open. Switch A manages the control board. Switch B usually connects to Sea Rays monitoring system.
Switch A is the issue. After the engine warms up, the threshold of the switch seems to open (and shut down the engine) even though there is more than sufficient operating oil pressure. What makes it particularily vexing to diagnose is that the switch appears fine when it is tested. In fact the generator will often restart and run fine then 10 minutes later will shut down and not restart.
If you find you are having these symptoms, switch A could be the issue. It is possible to bypass switch A to test the system by closing (jumping) the two leads going to the switch. However, that should be a short test since a real oil pressure problem could exist. I normally remove the switch and use a mechanical oil pressure gauge to test the oil pressure when I jump the leads.
This switch is used on both gas and diesel generators.
-John
Symptoms:
Generator starts, runs and randomly shuts down with or without a load after the engine has warmed up. What appears to be a fuel problem is actually the oil pressure switch opening which triggers the control board to shut the engine down. For clarity, there are two oil pressure switches on most Westerbeke generators. Switch "A" (37323) is normally OPEN and closes when the engine starts and oil pressure keeps it closed. Switch "B" is normally CLOSED and opens when the engine starts and oil pressure keeps it open. Switch A manages the control board. Switch B usually connects to Sea Rays monitoring system.
Switch A is the issue. After the engine warms up, the threshold of the switch seems to open (and shut down the engine) even though there is more than sufficient operating oil pressure. What makes it particularily vexing to diagnose is that the switch appears fine when it is tested. In fact the generator will often restart and run fine then 10 minutes later will shut down and not restart.
If you find you are having these symptoms, switch A could be the issue. It is possible to bypass switch A to test the system by closing (jumping) the two leads going to the switch. However, that should be a short test since a real oil pressure problem could exist. I normally remove the switch and use a mechanical oil pressure gauge to test the oil pressure when I jump the leads.
This switch is used on both gas and diesel generators.
-John