Mercruiser 5.0 MPI Catalyst - No issues

[Searay205]

Just posting my sensor laden Mercruiser catalyst control 5.0 MPI has had zero issues in 200 hours over three years. Usually sits 6 months in winter. Only issue prior to that was failed post Cat o2 sensors. They were removed along with catalyst and a simulator installed. Outdrive water pump is from 2019. and still shows 2.5psi pressure at idle as when it was new. No misfires to report. Runs beautifully. All saltwater use. Replaced manifolds about 4 years ago a complete waste of money. I busted them apart and found zero issues or corrosion. Boat is a 2011. New cat manifolds in my opinion are lifetime. They are heavy duty..

 

[CayugaCobalt]

Thanks for sharing this. Owning a 1997, cant imagine having another layer of complexity laid upon these already complex engines.

 

[Searay205]

yea the 5.0 mph went from 3 alarms, oil pressure, temperature and gear lube to 43 alarms.... Again no issues recently. If engine ever failed, I go back with carburated 350. The only benefit of catalyst is the catalyst manifolds will last as long or longer than engine. They are smooth, no corners and 3/8" thick. Extremely heavy.