See full version: How do you know if your outboard motor is overheating
The most common cause of outboard motor overheating is water pump failure. Lack of raw water flow and lack of fresh water can cause water pump failure. Lack of fresh water can be noted if there is a large increase in temperature between the inlet and and outlet of the heat exchanger.
Similarly, is the water coming out my outboard supposed to be hot? Increasing engine RPMs to a fast idle and higher should produce a strong stream of water exiting the outboard. The water coming out of the tell-tale is usually warm. If it's hot, that's often an indication of a blockage somewhere in the cooling system (and the flow probably won't be as strong as it should, either).
Beside above, how hot should a outboard motor run?
The most common causes of an overheating engine are: more
Other common causes might include a broken or damaged water pump belt that prevents proper pressurization and/or circulation, collapsed radiator hoses or a buildup of contaminants such as rust and road debris.
Never remove a radiator cap while the engine is still hot! The system is pressurized, and hot coolant will spray out and onto your face and arms.
If your vehicle overheats while driving, pull over and shut off the vehicle to assess the situation. Pop the hood and allow the engine to cool for 45 minutes. Opening the system and adding cold fluid while the engine is still hot is dangerous for both you and the engine. If there’s only a small leak, adding water will be good enough to get you to a NAPA Auto Parts store, but you’ll need to replace it with proper coolant so there’s no risk of damage in cold weather. If the level looks fine, carefully check the temperature of both top and bottom radiator hoses — if one is very hot and the other is not, this points to a thermostat that is stuck closed. [links]
Step-by-step instructions on how-to change your marine diesel fuel filter, check your steering system, replace a hose, remove and install boat graphics, outboard maintenance and so much more! more
Instead of fighting the current, here are some tips for using it to your advantage.
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Outside air and water temperatures have an effect on your boat engines operating temperature. [links]
Last but certainly not least, an internal engine issue could be causing the problem. This is something no boater wants, and usually requires the help of a professional to fix. Frequent maintenance can help prevent expensive problems such as corroded heat exchangers, failed gaskets, or clogged exhaust elbows from happening.
How-to fix: The water strainer is usually located close to the water intake, just follow the hose that goes from your water pump to the bottom of the hull. If your boat doesn’t have a strainer, or is outboard driven such as popular bass fishing boats and center consoles, don’t fret, there is still another place to look.
Weeds and plastic bags are almost always the first thing to check for when you hear the dreaded beeping or your temperature gauge goes into the red. As the boat’s water pump creates a hefty amount of suction, it is easy for debris to be sucked into and clog the raw water intake. Growth of sealife while the boat is at anchor can also clog water intakes.
How-to fix: To solve this, lift the stern drive or outboards and check to see if the little grate where the water goes in is all clear. For sailboats, inboards, and jet-skis, this may require a jump into the water to clear the water intakes.
Anytime you are working with the engines or entering the water, be sure to make sure the boat is turned off and the key is out. If entering the water, check your surroundings and water temperature. Only do so if it is safe, otherwise call a professional.
There are many reasons why you could have an overheating problem on your boat. Here are a few reasons why your boat may be overheating and how to fix it: