Yanmar alarm - Main throttle?

[SaltyDogGloucester]

Lost engine power while underway recently. After lots of troubleshooting, my husband found a loose fuse and popped it back into place. That gave us engine power back, however, now we have a constant alarm beeping from the Yanmar display panel. It says, “Main throttle sec throttle.” The red light stays on when you turn the key and beeps constantly.

Any ideas? We ran the engine for a bit and tried moving the throttle but it didn’t clear the alarms or beeping. It seems awfully coincidental that the fuse had popped loose and now we have this alarm but maybe totally unrelated? Feels like one step forward two steps back.

Thank you in advance for any help or guidance you can provide.

 

[Rode Trip]

Page 230 of the service manual https://www.marinedieselbasics.com/wp-content/uploads/edd/Yanmar-4BY-150-Service.pdf

It's either missing (disconnected) the throttle position sensors or they are shorted to ground. Sorry, I can't help you actually finding the sensor other than to suggest looking on the engine where the throttle cable is connected.