mysterious alarm going off 31PC


S

Sempre 31

New member
hi Forum, hoping you can help me diagnose; Boat runs great, underway, cruising for over 30 minutes when alarm goes off.
all gauges/temps ok, fluids all ok, no leaks/bilge issues. the alarm sounder on this boat is the same for every function and there is no screen that informs whats wrong.
i shut off each engine and find that the alarm stays off if the port engine is off-. return to marina on starboard only
-next time out- alarm does not go off
- next time out alarm goes off
-next time out alarm does not go off
-this past weekend, alarm goes off- we return again on one engine
Mercruiser mechanics(marinemax) who take care of tbe boat put computer on engines and no codes come up. they have not been able to diagnose.
any ideas? sensor gone bad? alarm worn out?
ping me at gag6463@gmail.com with any ideas. thanks!
Greg
 
Formula suggests to check all battery load/strength, anyone seen that?

Sempre 31 said:
hi Forum, hoping you can help me diagnose; Boat runs great, underway, cruising for over 30 minutes when alarm goes off.
all gauges/temps ok, fluids all ok, no leaks/bilge issues. the alarm sounder on this boat is the same for every function and there is no screen that informs whats wrong.
i shut off each engine and find that the alarm stays off if the port engine is off-. return to marina on starboard only
-next time out- alarm does not go off
- next time out alarm goes off
-next time out alarm does not go off
-this past weekend, alarm goes off- we return again on one engine
Mercruiser mechanics(marinemax) who take care of tbe boat put computer on engines and no codes come up. they have not been able to diagnose.
any ideas? sensor gone bad? alarm worn out?
ping me at gag6463@gmail.com with any ideas. thanks!
Greg
Click to expand...
Formula advises that sometimes it can be triggered by a battery with low power/needing replacement... anyone had this experience?
 
Is it a solid alarm or beeps?
If solid check the CO alarm in the cabin and the high water alarm in the bilge
 
hi Gents, yes to all of the above- solid alarm sound, all fluids topped off, mechanic could not confirm co2 sensor in cabin as culprit... maybe its possible? other ideas appreciated! Formula advised to check battery load so i'm hopefully doing that today. keep em coming
 
Things like the drive lube bottle would not set a code. Might be a hung or bad switch, disconnect the lube bottle. Could also be a chaffed tan/blue wire coming from the alarm. What motors do you have?
 
List of alarms, and I'm thinking its might be the water pressure alarm, because it fails most often and may not set a code.
Also note serial numbers 0m00000 and above

Codes 496.jpg
 
Fume detector is a solid alarm. On my 34 PC the alarm module is starboard side below throttles. Won't show up on computer. Mine sometimes alarms during high heat, when I first turn on the batteries. Alarm will silence itself if no fumes but there is also a mute button.
 
thanks guys, super helpful, it looks like the culprit is manifolds overheating... believe it or not, i think they are the originals. I bought the boat 5 years ago and have not changed them yet. they look like the originals but i cant tell for sure. either way I certainly have gotten more time on them than youre supposed to. with aluminum risers i will only have to replace exhaust manifolds. ah joys of boating- just replaced the AC water pump and engine box ram lift myself,,, manifolds are past my pay grade.
 
For what it's worth, I had a similar issue last season. Ended up being an oil pressure sensor that went bad. Quick trip to AutoZone and a new $8 GM oil pressure sensor got my issues straightened out pretty easily.
 
I just went through several months of trying to track down the same problem. Mechanic read the error code as a General Warning No 1. Volvo said to replace they ECM, but of course there are none in stock. I sent the ECM to a third party tester and it tested fine. I ended up buying a Diacom code scanner and put the ECM back in, and within 20 min I found a bad exhaust manifold temp sensor. I solved my own problem with a $30 part after spending over $1000 with the mechanic who could not find the problem.
 
You must log in or register to reply here.
Back
Top