Have a 2018 Sea Ray SPX 210 stern drive with a Mercruiser 5.7L 200 hp. Bought used in 2021 in Florida. Salt use vast majority of 250 hours. O2 sensor alarms after slowing down for wake zones in icw areas only, never lakes.
Local dealer replaced o2 pre and then after more alarms post. Second round of o2 alarm notices, independent service diagnosis guy said major internal engine issues. No rough idle or running, no white smoke. Safe mode alarmed in but typically could run under 3000 rom to get back to dock.
Dealer then said Mercury would offer 4” riser parts for exhaust manifolds since no risers oroginally installed this model year. Sea Ray picked up labor after pushing dealer. Oil replaced because dealer said filter was wrong and oil pressure ran little low. O2’s not replaced after riser installs. Ten year old blog on exact mercruiser lack of riser issues exist but manufacturer evades design fault.
Next time out just weeks later, engine started slow but did start and run but then wouldn’t start. Also stern drive unit trim sticking.
Charged battery and ran it on earmuffs in driveway 15 minutes. Alarms returned. Trim alarm and o2 again.
Dealer fixed trim and said o2 not related to old riser. Other o2’s not corroded after asked them to check. After dealer lake test, boat alarmed again with oil warnings. Now water in oil, zero compression in one cylinder, another cylinder low compression, camera scope shows bent valve.
Could this be hydro lock pre riser install? Can water get through that catalyst?
Should I try just checking or rebuilding heads or bite bullet and replace engine with exhaust manifolds etc…?
Mercruiser or aftermarket heads and engine?
Appreciate it.
Local dealer replaced o2 pre and then after more alarms post. Second round of o2 alarm notices, independent service diagnosis guy said major internal engine issues. No rough idle or running, no white smoke. Safe mode alarmed in but typically could run under 3000 rom to get back to dock.
Dealer then said Mercury would offer 4” riser parts for exhaust manifolds since no risers oroginally installed this model year. Sea Ray picked up labor after pushing dealer. Oil replaced because dealer said filter was wrong and oil pressure ran little low. O2’s not replaced after riser installs. Ten year old blog on exact mercruiser lack of riser issues exist but manufacturer evades design fault.
Next time out just weeks later, engine started slow but did start and run but then wouldn’t start. Also stern drive unit trim sticking.
Charged battery and ran it on earmuffs in driveway 15 minutes. Alarms returned. Trim alarm and o2 again.
Dealer fixed trim and said o2 not related to old riser. Other o2’s not corroded after asked them to check. After dealer lake test, boat alarmed again with oil warnings. Now water in oil, zero compression in one cylinder, another cylinder low compression, camera scope shows bent valve.
Could this be hydro lock pre riser install? Can water get through that catalyst?
Should I try just checking or rebuilding heads or bite bullet and replace engine with exhaust manifolds etc…?
Mercruiser or aftermarket heads and engine?
Appreciate it.