RexAnnie":yqdtpogu said:
Another prudent item to execute is to close the raw water through hull valve when ring towed. I’ve read Sea Tow does that on tows. Our back flow source was through the cutlass bearing cooling line.
Safe travels.
I realize that you were told that the injection point of the water that Hydrolocked the engine was from the cutlass/packing cooling hose back feeding to the exhaust elbow. This happened in a event that the boat was not being towed?
RexAnnie":yqdtpogu said:
We have never been towed.
This is hard to believe. The connection point of the packing/Cutlass cooling hose is under the after cooler. There is a tee connection there, up stream side of the hose connected to the tee connection goes to the after cooler/heat exchanger. The down stream side of the tee connection goes to the reverse gear cooler. The hose connected to the downstream side of the reverse gear cooler is at the same elevation as the exhaust muffler. The hose does a 65 degree turn goes up to the exhaust elbow. The exhaust elbow water jacket fills with water that is supplied by the raw water cooling system via the hose that comes from the reverse gear cooler. On the bottom of the exhaust elbow ( portion facing down there are shower nozzles or ports that allow the water to cool the hot exhaust when the engine is running. The nozzles or ports are slightly higher than the exhaust muffler or "can". The water fills the can and by way of the engine running ,exhaust pressure pushes the water out of the can. The water exits the can into the exhaust outlet hose and hull exhaust port.
Click on this photo. Look at the Tee connection below the after cooler. Two hose clamps close together. This is where the cutlass/packing gland hose gets the water for cooling. Look at the elevation. It is lower than the muffler inlet connection.
https://cdn.yachtbroker.org/images/high ... d53_97.jpg
The R31, the most likely way that that engine in this installation would ingest water is the thru hull engine raw water pick up. If it is being towed. It is highly unlikely that it would be through the Cutlass/packing gland cooling port. But you said the boat was not towed.
Was the boat lifted off a trailer with a travel lift, was the boat towed over the road and then lifted by a travel lift, did the boat get launched at a boat ramp that had a steep incline, any of theses Before the water ingestion ? If yes to any of those conditions that would make more sense to the cause of the hydrolock. Water back feeding up the exhaust into the turbo and exhaust manifold causing the cylinders to fill with water. The solution that Osprey stated would have prevented this from happening. The Exhaust system installed in all of the Ranger inboards is marginal. The difference of 1" or 2" of elevation of the exhaust hose could be the difference of water getting into the engine when floating statically, being towed over land, launched at a steep ramp, or lifted by a travel lift.
I mentioned the use of a travel lift. Many times a travel lift operator will pick a boat up and when moving it to the pit to launch it he/she will drop the bow a bit and carry the boat stern high. If this is done in your R31 with a exhaust system that has water in it ( exhaust can or Muffler) there is a chance that the water will drain out of the can into the riser dry side and ingest water into the turbo and exhaust manifold filling the cylinders with water.
Why am I posting this? I'm sure you are on your way by now doing the Loop and have the engine issues repaired. The Cutlass /packing cooling line should not be ruled out as a cause but in my opinion it wasn't the cause based on the information that you posted. The boat was not towed in the water. Being towed meaning 5 mph + for an extended period of time. Cutlass/packing cooling hose is 3/8", the water volume and pressure that would be created from towing the boat would be minimal. The tee location on the D4 and D6 is not the same as D3 or Yanmar used in the R27, R25 or C26. I am posting this so you have an awareness of other possible causes so this does not happen to you again in your R31. Does your exhaust muffler have a slosh knob on the bottom of it?
This picture shows the Knob on the bottom of the can. This helps eliminate the water from slushing up the exhaust hose into the dry side of the exhaust elbow.
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This is a D3. Notice the Tee fitting for the Cutlass/packing gland coolant hose mounted high at the same level as the exhaust elbow. This installation is more likely to get water ingestion from the gland coolant hose.
If you don't have that knob you would be wise to do an installation like Osprey described. Drain the exhaust when towing over the road, lifting the boat with a travel lift, winterizing.......
What happened to RexAnnie could happen to anyone if the right conditions exist.