overheating boat engine

You are cruising along in your primary boat, or maybe during on excursion in your tender, when suddenly you see your temperature gauge starting to creep up out of the normal, and into the red range.

Overheating is one of the main cause of marine engine breakdown. What do you do, when you see your engine start to overheat to avoid a serious problem?

The most common, and likely cause of an overheating engine is a clogged intake.

debris can clog engines

Floating Debris Just Waiting to Foul Your Engines!

A clog is usually caused by sucking up trash, plastic, weeds, etc. That is what you should check for first by:

  • Immediately shutting down the engine.
  • Drift for a while to allow the debris that “could” be blocking the intake to float free on its own while the engine cools. Once the engine cools, you could try to drive in reverse under power to try to dislodge it.
  • While the engine is off and cooling, open the engine room hatch and check the sea strainer.
  • Be sure to close the through-hull valve before taking the top off the strainer.
  • Once the wing nuts have been removed, take out the strainer basket and check for debris.
  • If there is no debris, gently “crack” the through hull valve to see if you have raw water flow from the outside coming into the strainer.
  • If you do not have water flow you know the intake is definitely clogged.


If you can clear the intake, and see that water is flowing, you can safely get under way, but watch that temperature gauge.

If a clogged intake is not the problem, you may have something more serious to contend with such as a water pump malfunction, water leak, etc. Unless you are, or have a skilled marine mechanic or engineer on board, it is probably best to radio for Sea Tow, rather than attempt to do further trouble shooting and repairs on your own.

Avoid Overheating and Other Engine Trouble

Of course the best way to deal with overheating, or other engine trouble, is to try to avoid problems in the first place, through proper maintenance.

Your motor yacht’s engines probably need the most routine care to keep them running trouble free, as long as possible. A marine engine is a complex machine. Within the engine are several “systems,” each of which need to be well monitored and maintained to avoid more costly repairs, or worse yet, a breakdown at sea!

  • Fuel System – The fuel system needs to be checked regularly for any leaks, clogged lines and/or dirty filters. Filters need to be replaced on a regular basis
  • Cooling System – As covered in this article, a major cause of engine failure is overheating. Your cooling system must be well maintained. Of course, coolant levels need to be checked regularly, and as in the fuel system, you need to check for any leaks. In addition, you need to check and replace any weak hoses, and/or belts.
  • Air System – Your engines also have an air system, they need air for combustion. The air system has filters that need to be regularly checked and replaced as needed.
  • Oil System – Like on your car, or any engine for that matter, oil is the “lifeblood” of your yacht’s engine. The oil system must be routinely checked for leaks, filters must be changed, and the oil itself needs to be changed (but not as often as on a car) to prevent oil viscosity breakdown and severe engine damage.
marine engine repair

Routine Maintenance Avoids Costly Repairs!

The Value of Routine Maintenance

Routine maintenance saves you on costly repairs, and extends the life of your yacht. It also helps to maintain her value when it becomes time to sell. One way to ensure that your yacht is getting all the regular workouts and upkeep she needs, is to sign up for our On Demand Yachting or Charter Income programs.



Operating a motor yacht can be costly. You can reduce your expenses, and avoid costly repairs by keeping her well maintained. On Demand yachting from FYM can help. If you would like to learn more, or if you have any questions or comments about this blog post, do not hesitate to contact our Yacht Management specialists, or call us at (954) 900-9968.