Hydro Locking confusion

kbgolf1

My mechanic has been working on my boat since June 22nd due to getting an alarm on my port engine.  It was getting hydro locked and they kept thinking they fixed the issue.  Here is what the guy is saying now.  Just doesn't make sense to me (please advise or point me to a good mechanic in the Annapolis, MD area that can/will help).... 

We had it fail to start and hydrolock on us today for the first time so we got to see what you are seeing. The water came in through the exhaust when the engine tried to run backwards a revolution or two during a backfire. The cause of the backfire is the same as what was preventing the engine from starting consistently. We believe the cap and rotor was shorting out and causing the misfire. The boat started consistently since the repair. Going back to the discussion about the water incursion, It is concerning to me. The factory exhaust height may need to be raised 3 inches and they make a kit for this but it is not cheap (2,500.00 parts and labor). The original problem was the two failed injectors. The manual cylinder drop test confirmed their failure. Their replacement and seatrial confirmed that this part was fixed. We replaced the cap and rotor on both engines and the starter and exhaust gasket on the port engine.

Michael T

Has the engine height (from stringers) been altered in any way, thereby changing the relationship of the riser height to the waterline?

jimzimm

SAme problem on the port engine on my 2002 342 FV with 6.2 mercs. This side of boat sits low due to all the weight on this side. If you have mercs w/IO have the mechanic check the exhaust flappers just below the exhaust riser. Mine where gone and rouge wave in the marina caused water to back into cylinders and cause hydrolock. Fixed problem and has been correct for 200+ hours.

Michael T

If your flappers are gone/damaged enough sudden stops from on plane and even backing down a ramp too hard can cause water intrusion.