Intermittent Alarm

[jlanza14]

I need some help figuring out an intermittent alarm that I was getting last weekend on the boat. I have a 2500 SCR with a 5.7. The original motor that came with the boat failed about 3 years ago and I replaced it with a used motor before this season. The used motor I had put in has a serial number of L652275. When I first put the boat in the water it wasn't shifting right and we determined that it was because the shift interrupter wasn't working. The reason it wasn't working is because the ICM is for a Bravo and doesn't have the shift interrupt programmed into it. I got around this issue by tapping into the distributor sensor and grounding it when the switch is engaged. The reason for this background information is because I'm wondering if the Bravo ICM is the cause of my intermittent alarm. I see in the wiring diagram that the water temp sensor goes into the ICM and the ICM is supposed to sound the alarm. Does anyone know if the Bravo ICM would have a different alarm setting then the Alpha? Also it appears that the only thing that is Bravo on this motor is the ICM as it doesn't seem to have the raw water pump on the engine. I took the plug off the water sensor and jumped the yellow and black wires together but the alarm didn't go off. I was thinking that maybe the ICM reads the ohn reading from this sensor and sets off the alarm at a certain temperature? I also changed the thermostat, temp sender and temp gauge and the gauge never goes above 175 and with an IR gun the reading on the thermostat housing is 155-160 so I don't think it truly is overheating. Any insight anyone has to the differences between the Bravo ICM and Alpha ICM are appreciated before I go and buy the $700 Alpha ICM.

Thanks!