HYDROLOCK 270 FV Exhaust Water Shutters
2002 Fv 270 Merc. 5.7 Mag MPI / Bravo 3
I experienced the dreaded hydrolock at the end of the summer and have been chasing gremlins since. Boat is still in the water and temps are dropping, so timing is of the essence. May be towing it from the marina and onto the trailer if I can’t get it running soon.
I have the spark plugs out, cylinders lubed (if it matters at this point), and risers and manifolds off for pressure testing and inspection. I ran a compression test and there were no major variances in all 8 cylinders. All around 130psi, but I forgot to hold throttle at WOT while performing the test, so I may need to re-perform. I initially pumped the milky oil out with a 12v pump from the oil drain hose and flushed 2x’s with fresh oil. I replaced starboard exhaust riser gasket thinking that was my corrosion / water intrusion point, only to re-assemble and discover that I was still getting water in the engine. It would run, but hard to start and very rough. I’ve replaced every sensor on the intake, rotor and cap, plugs and wires, fuel filters, etc. thinking that I had a fuel delivery issue additionally. Turns out the dead mis was tied to the continued hydrolock / fouled plug(s), or possibly engine damage.
My question is re: lower y exhaust and water shutters. Does the boat need to be out of the water to replace these exhaust shutters? When I pulled the intermediate pipe (elbow) and hoses on both sides of the engine, water came gushing in the bilge, so I quickly replaced. Does the “wet exhaust” start at this point (lower Y pipe) or is the purpose of the water shutters?
The plan is to flush the oil and change filter again, install new water shutters, riser/manifold gaskets (possibly new riser/manifolds), new plugs and fire to see if I have solved the water intrusion issue or if it is a head gasket/ bent valve, etc. that will require the motor to be pulled and rebuilt. Additionally, should I reassemble at this point to see if I have fixed the problem with exhaust parts/gaskets or continue on and inspect valves, head gaskets at this point?
Stumped and need guidance/direction on how far to proceed with the boat still in the marina slip.
Post edited by Ripple270 on