Outboard engines types:
We should begin identifying outboard engines available on the market, to identify their particularities, and care and maintenance recommended procedures.
Two-stroke gasoline outboard
They were the first outboard motors to be manufactured, mainly due to their mechanical simplicity which is derived from two-stroke motorcycle engines. These have much fewer moving mechanical components and the advantage of providing power to the shaft with every turn of the crankshaft with an explosion on each turn of the motor shaft. This means that the power/weight ratio is advantageous because fewer parts means less weight and a power cycle is added for each turn of the crankshaft.
Their volume and their weight are therefore lower and consequently, they are easy and cheap engines to manufacture, which made them very popular in the beginning.
Four-stroke gasoline outboard
Four-stroke engines are derived from their counterparts used in private vehicles, with a somewhat higher power output than two-stroke engines and much more efficient due to burning fuel efficiently and being able to dispense lubricating oil into the fuel mixture. Although they require two turns of the crankshaft to generate a power cycle, have more moving mechanical components and are obviously heavier and are more expensive to produce than two strokes, they usually have a power-to-weight ratio equal to or better than that of a two-stroke engine.
Four-stroke diesel outboard
Not as common or popular as two and four-stroke petrol engines, there are some commercial versions that are quite successful, especially because they have a much greater autonomy than gasoline engines and a much lower operating risk due to the lower explosiveness of diesel fuel compared to petrol.
Causes of outboard engine overheating:
All outboard motors, such as thermal machines that burn fuel (heat) in movement and power, depend on adequate refrigeration or cooling of some of its components in order to function properly and efficiently, and, if not properly cooled, may increase the risk of overheating which can destroy your engine.
Fortunately, almost all two and four-stroke petrol or diesel outboard engines have shields and alarm devices to prevent the destruction of the engine, so it is important to pay attention to the following symptoms or causes:
- Low or insufficient flow of seawater to cool the engine. This can be observed and detected in that “trickle” of water that engines tend to expel out the side.
- Obstructions due to marine dirt (snails or algae) or foreign elements such as plastic bags. Damage to the thermostat that prevents its correct operation.
- Damage to the suction pump and cooling water circulation (sea water).
- Excess fuel mixture in the combustion raising the normal operating temperature of the engine.
- Use of a propeller that is not suitable for the power/speed ratio and the type of hull, or damage due to blows or breakage that does not allow the creation of the necessary flow of propulsion causing the engine to rotate at many turns creating too little power.
Therefore, at any sign of overheating of the outboard motor, check the presence of obstructions in the engine seawater intake grilles, damage to the propeller, or see if the engine is operating at too low or too high a speed (forced engine). Consult with an expert naval mechanic who, after testing the engine, can give you a diagnosis of the cause of the problem and the most economical solution for it.
How to maintain our outboard engine:
We have all heard that “life is better at sea”, but the reality is that when we go sailing we find ourselves alone at sea with only the safety and confidence in our boat providing us belief in the “superiority of being at sea.” Without this confidence, a happy voyage can turn into a bad memory.
Outboard engines, like any machine with mechanical elements, are subject to revision, care, maintenance and repairs, which must be entrusted to professionals who know the sea and the equipment used in it. This ensures that our motor will always be functional and safe to undertake any boating activity and we will be able to enjoy our boat with complete confidence and security.
First, contact professionals who know your engine (brand-specific technical service) and who therefore follow the protocols and recommendations for inspection and maintenance of your engine with the correct tools and replacing the necessary components with original parts.
Among the general basic recommendations that almost all manufacturers suggest is an annual review, preferably to be done before the season of frequent use of the engine (summer), for a tune-up, change of filters and lubricants, general cleaning and testing to detect potential failures that can leave us “drifting” without propulsion or that prevent us from enjoying our boat journey in a timely manner. Depending on the accumulated hours of operation, check and change the impellers of the saltwater pumps that cool our engine, change the thermostat if necessary (for hours of use), spark plugs, accessory belts and, above all, the cathodic protection anodes, both internally to the engine, and externally located in the trim and tail. These protect the metal parts of the engine from marine corrosion with the use of a “Galvanic cell” manipulating the electrical conductivity of seawater.
Finally, review of the fuel lines to detect and correct leaks, and review of the electrical installation of the engine and the boat to guarantee a timely and safe start.
Frequent prevent maintenance:
Every time we use our engine, we must pay attention to certain details before using the engine and after its use.
Before using the outboard engine:
- Measure the engine oil level and externally check it for any anomalies such as oil stains or excessive smell of gasoline.
- Check the fuel-water separator filter, especially if it has a transparent inspection hood.
- Check the propeller for any damage and check the lower part of the engine tail for possible oil leaks.
- Start the engine and verify that it starts correctly, without difficulties or too slowly and let it idle for a while to observe its “smooth” operation.
If you have any doubts, consult a professional, it will cost you much less than a major engine repair or having to replace it with a new one.
In two-stroke gasoline engines:
- Make sure you have correctly mixed the gasoline and two-stroke oil in the tank in those engines that do not have an automatic oil injection system.
- In engines with a direct injection system, check and fill the level of two-stroke oil in the tank going to the engine twice.
Don’t forget, not doing this check can seriously damage your outboard motor.
After using the outboard:
It is important after using the outboard motor to wash it with fresh water, whether the boat is left afloat in the marina or taken out of the water to store on land, modern engines have a freshwater intake to which a water supply hose from the port can be fitted to displace the salt water inside the engine block. Immediately raise the tail out of the water in the case of leaving the boat docked afloat, this will significantly reduce the effect of galvanic corrosion due to potential differential between the different metals that make up the engine.
Preventive maintenance -end of season:
At the end of the season of use of the boat, either due to the end of the holidays or because the good weather is over, it is very likely that we will remove the boat from the sea and store it in a “dry marina” to avoid prolonged exposure of the ship to the effects of sea water, in addition to damages derived from bad weather and storms.
At this time we must take the opportunity to do the so-called “winter storage“, which is nothing more than a deep washing of the engine with seawater and carrying out the maintenance routines that each engine manufacturer recommends to extend the useful life of the engine. With this we avoid the act of corrosion derived from inopportune saltwater deposits and a prolonged stoppage of the engine as much as possible. After doing this we can ensure that for the next season of use of the engine, after routine maintenance, it will not only start first time but it will also retain all the safety and reliability offered by the engine manufacturer.