Here is one of my bigger tows. Not sure what it weighs, but it's a heavy boat. 76 miles to deliver, EVIC showed 16.7 mpg. Even my buddy that went with me said it towed better than his Silverado 3/4 ton gas truck!
Seems strange that Mercury can make an outboard that handles the salt water and chooses not to make an outdrive that will. I agree that fresh water cooling of the engine is mandatory in salt water. My Volvo diesel inboards have them here even in fresh water. They don't make them a different way and that is fine.Vern - Good guess. Towable for short and flat terrain. This is a model they no longer make.
HOWIE - ... that Mercruiser outdrive. Actually all of the major outdrive units fail in a saltwater environment. Before even getting into the details always remember that those outdrives have a large rubber boot that flexes as it moves. If that rather flimsy rubber boot tears, the boat flat out sinks. It happens frequently. The reliability of all those parts, many touted as stainless and resistant, is very poor around salt water. Corrosion builds mostly inside from increased galvanic action. Marina mechanics earn a living dealing with and replacing those things on newbies bringing their boats to saltwater areas.
Short visits OK. Long term usage is a near total failure. That's why you see saltwater boats with one, two, three and even four outboards on them. They work and their coolant design is very resistant to galvanic corrosion with proper anodes and lower-unit construction. They are most always FLUSHED with fresh water after each usage. Not so easy to do with inboard engines and outdrives.
Now the engine in an I/O could have two different cooling systems. Most traditional for freshwater is raw-water cooling. Water in - water out. Not a problem in fresh water. Put one in saltwater and you have that going through the engine. You don't want to know.
The other coolant for inboards is to have a closed coolant system for the engine and a radiator/heat exchanger exposed to that saltwater cooling outside the engine. Made properly, that works way better. The racing boats you see throwing all that raw water out are not made for longevity. Just the cost of doing business.
Good question.
Sure would disagree that they "Choose" to make an outdrive that does not handle salt environment. The probably don't care as it lasts long enough to make it out of warranty, normally. There is a good reason Mercury motors are referred to as boat anchors.Seems strange that Mercury can make an outboard that handles the salt water and chooses not to make an outdrive that will. I agree that fresh water cooling of the engine is mandatory in salt water. My Volvo diesel inboards have them here even in fresh water. They don't make them a different way and that is fine.
I assume a typo and you meant "lifted"?Of course all outdrives have sacrificial anodes. What breaks on the outdrives is shift mechanisms, , hydraulic systems, internal gearings, water passages the corrode, boots that tear and leak, oil seals that don't, gear sets that trash and more. Very unreliable.
Also something fun is the old OMC outdrives could be listen (sp lifted?) out of the water. The newer ones not so much. People stick them in the sand and tear off the skegs because they do not lift way up to clear obstructions. Then they suck sand and other debris into the ports, tearing up the impellers, blobbing the intake ports and cause overheat damage.
What should happen and what does happen are two different things.
Oh - 10 gag grouper this morning in just 2 hours of fishing. Up to 104 into the boat since June 1st.