Thanks in advance for any help. Just don't want to go down the path of replacing sensors without a game plan, they can get expensive particularly if not solving the problem. I was out this past weekend when my alarm went off while idling under a bridge (had been running all day w no issues). Motors are 2005 twin 525 efi w 150 hours, 5 beeps every couple minutes. In any case the motors kept running fine with no apparent issues or being reduced in power. Made it back and pulled codes. Here's what I found..these were all on the starboard motor, no codes on the port. Question is, do I start with the cam sensor and run the motor to see if any codes reappear. Do I replace both the cam and Idle map...?. Are they related some how? Im as for as I can go knowledge wise when it comes to these type issues. Again, thank you for any advise.

#77 cam sensor
#19 overspeed ( I get this one, from hitting the rev limiter)
#17 Idle map STR
#21 overHT ( water temp never got over 160, oil temp never got over about 210 idling, usually 180 while running)

^^^ Funny our group had the same beep and alarm (cam sensor) last weekend as well on 2005 525's as well. No issues just had the beeps. Scanned it once back at the marina.

Replaced the cam sensor last night. (amazon overnight shipping). So far so good running on the hose. Will test this weekend on the river. FYI cam sensor is fricking expensive from Merc. if you can find one. Search for AC Delco PN: 213-350. Thread over on PBN on our problem/ cam sensor alarm.

#17 Idle map I have never dealt with. But I would also replace it or at least have it on hand. EZ to replace on the water / at the marina

Your cam sensor may be different, look up your engine serial number and then you will know which cam sensor you have. In our previous boat we had 05 525s and starboard showed near the same codes as what you put up, replaced cam sensor and all was good.

Thanks for the info. I may post under the general forum as well to see if any other thoughts. Thx again.