Hello again. Figured I’d start a new thread coming off my old one asking for a scan tool recommendation. Of course a few hours after the Diacom I ordered shipped a gentleman I know local to me (also in Tom’s River, NJ) offered to loan me his tech scanner. Was able to scan my engines….
So yesterday my starboard engine had a Guardian fault then today it had no guardian fault and at key on ignition off it had no faults. Turned engine on, with muffs and a code for “Mercury Fault 3 Sea Pump Low Pressure” my first guess would be to change the impeller and see what happens, however the previous owner told me both impellers were new with 0 hours at time of purchase. I’ve read pulling the impellers on 8.2 Mags is a b***** so I figured I’d see if anyone else has experienced this. I’m a little confused because there doesn’t appear to be a pressure sensor on my pump so I’m not sure where this sensor detecting this trouble would be. I know on my hydraulic cooler on the rear of the engine there is a pressure switch for the power steering I believe but I don’t see anything for seawater pump pressure. Any tips/hints?

Also ended up scanning the port engine and finding a trim limit fault but I figured I’d leave that be as my new trim senders and limits will arrive in about a week and a half, no point is investigating when I have old senders installed that have beat up wiring.

-Dylan

The switch on the cooler is the sea water pressure sensor

Seeing trim limit fault can be a non-issue if you don't have digital trim senders. Most have the standard analog limit/sender and the errors are always there but does not pose a problem for the motor