Someone that knows how to scan and read and understand the scan that has Merc G3. Also find someone that knows these engines and the cat systems. that's the best answer I can give without the product in front of me. Also the dealer can run your engine serial numbers to see if there is any software updates and parts and service bulletins. At least do that every couple times per year bare min as well.

Side note Volvo Penta Cat engines seem to be more reliable than Merc especially anything against the Merc 8.2. Merc is the only one doing a 8.2 anyways. Always seems to be a problem with cooling them

Thanks, I appreciate the advice. Just astonished how bad customer service from dealers these days, prob my last new boat as a result. Again thanks,

Keith