OK, problem solved. The engine has *two* oil pressure switches and one oil pressure sender (for the gauge). The sender and one of the switches are together on a tee connector, low on the port side. I'm not sure what that switch is for. But the switch for the audio alarm circuit is separate, it...
Huh, now this is interesting... Page 4E-2 is my engine, but the diagram is about the same. I see now that there are TWO "oil switches" in that circuit diagram. One of them is in the audio warning circuit (Group C, item 1), and one of them is in the "ignition" circuit (Group B, item 5). The...
Well, that is my understanding of how the alarm circuit is supposed to work, but I try to keep an open mind... The logic is that there is no oil pressure when the engine is not running, so if you have an alarm switch for "no oil pressure", then it will be activated from the moment you turn the...
I have twin Mercruiser GM EFI 5.0L V-8 2 bbl engines (1999-2001) with Thunderbolt V ignition. Engine serial 0L639284 / 0L639281. When I start the port engine, the audio alarm buzzer sounds for a few seconds until the engine generates oil pressure, as expected. But when I start the starboard...
