6 Everyday Practices for Your Marine Engine

January 4, 2017 - 9:00 AM by Samantha Pudney

driving-speedboat

Starting your marine engine after a few months off the water? A refreshed understanding of the mechanics of your boat are highly recommended for a healthy start-up.

Although most of us consider ourselves master of best practice, it can be tempting to cut some corners when it comes to maintenance which could damage your engine. Check to see that you are carrying out these everyday best practices to increase the longevity of your engine.

1. Use a Cold Starting Aid

NB: This information is more relevant to indirect diesel injection engines

While the weather is warm most engines don’t need any type of cold start procedure and are able to fire immediately. But slow running engines will need some extra help from their cold starting aid, especially if it is the type that delivers extra fuel.

Keep your gearbox in neutral, then start the engine using the starter motor and push the button or turn the key. If your engine is unwilling to start up, return to your cold starting procedure to ensure that there is no damage inflicted on your engine.

If 15 seconds have passed and you are still stuck in silence, switch off your engine and wait for all of the moving parts to stop. Let the starter motor cool down for approximately 30 seconds before you try again. If it still won’t start, turn off the raw cooling water at the inlet valve to prevent your exhaust filling up with water.

2. Speed Proportionate to Power

Your optimum cruising speed will always depend on the design, weight, propeller size and power of your marine engine. Thus, this will be different between individual models. The speed of a displacement hull is subject to a formula based on its waterline length; generally 20% below the maximum speed.

Pushing any displacement boat even just a touch faster than it is designed to handle naturally requires a disproportionate amount of power. This is bad news for the health of your engine. Allowances, however, can be made for extenuating circumstances including strong winds and currents.

3. Check the Size of Your Propeller

A propeller that is able to drive your yacht at its designed maximum speed and maximum engine rev’s achieved is optimal. You will need your engine to produce enough power to achieve this speed in addition to driving supplementary items such as the alternator. The ideal combination of both engine and propeller produces a maximum boat speed at 80% of the maximum engine speed.

If your propeller is too small then it will result in a low boat speed. On the other hand, if your propeller is oversized it will overload the engine before optimum boat speed and maximum engine rev’s can be achieved. This will produce billows of black smoke as a result of the burnt leftover fuel.

a-yacht

4. Warming up Your Engine

The majority of marine engines require a warm up time of around 10 minutes. This also charges your batteries. Then, it’s time for a few quick checks from your end:

  • Oil pressure: confirm that the light is switched off, the buzzer is silent and that the gauge is reading the recommended oil pressure.
  • Cooling water gauge: check the temperature, if it is higher than usual then review the supply to the engine.
  • Engine noise: listen to the sound of your engine running. If you hear anything unusual then reduce speed, put the gearbox in neutral and take some time to investigate. Often, a buildup of debris around the propeller is the problem.

5. Shutting Down the Engine

When your day out sailing reaches the end, reduce engine speed to tickover. Then put the gearbox in neutral before pressing the fuel stop switch or pulling the cable. At this point, it is important that you do not turn off the key switch before the engine has completely stopped.

This could cause serious damage to your electrical system, as when you hit the stop switch or cable it operates a cut-off on the fuel injection pump. Only once your engine has stopped should you reset this and turn the starter key to the off position.

6. Sailing with Engine Stopped & Mechanical Type cone clutch gear box

Fixed Propellers

Once your engine has come to a complete stop, you will need to engage the reverse gear and lock the shaft into place. This manoeuvre will prevent the propeller from rotating, which can cause wear in both the gearbox and stern gland, however if the gearbox is a cone clutch type then cone slippage could be introduced with the possibility that the clutch will not disengage when restarting the engine.

NB. Option is to fit shaft break.

If you have a yacht with a folder propeller, place the control lever in the neutral position. If your yacht has two-bladed propellers, line up with the propeller in order to reduce drag. Then, mark the inner end of the propeller position from inside your boat.

When mechanical cone clutch type gearbox or sail drive is equipped with the following propeller:

  1. Fixed propeller:When sailing under sail with engine operation stopped put control lever into Neutral. The output shaft keeps rotating.Notice:When control lever is put in Reverse position, cone slippage will be introduced and there is possibility that the clutch doesn’t disengage. This can be a problem for engine re-starting.

    There are options to stop free rotation of propeller-shaft if you don’t want to occur noise from rotating propeller:

    1. For sail drive: install folding propeller or Feathering propeller instead of fixed propeller.
    2. For marine gear: install the Shaft – Lock device, on the propeller shaft.
  2. Folding propeller:When sailing under sail with engine operation stopped put control lever into Reverse position, this to operate the folding propeller to fold close blade and output-shaft stops from rotating. After this operation put the control lever back into Neutral.
  3. Feathering propeller:When sailing under sail with engine operation stopped put control lever into Reverse position, this to operate the feathering propeller into feathering position and output-shaft stops from rotating. After this operation put the control lever back into Neutral.

When mechanical dog clutch or mechanical disc clutch is equipped with the following propeller:

  1. Fixed propeller:When sailing under sail with motor stopped put control lever into Neutral. The output shaft keeps rotating.Notice:
    When control lever is put in Reverse position there is a possibility the clutch does not disengage.
    This can be a problem for engine re-starting.There are Options to stop free rotation on propeller shaft if you don’t want to occur noise by rotating:

    1. For sail drive: install folding propeller or Feathering propeller instead of fixed propeller.
    2. For marine gear: install the Shaft-Lock device, on the propeller shaft
  2. Folding propeller:When sailing under sail with engine stopped put control lever into reverse position, this enables the folding propeller to fold close blade and output-shaft stops from rotating. After this operation put the control lever back into neutral or remain reverse position as you like.
  3. Feathering propeller:When sailing under sail with engine stopped put control lever into reverse position, this enables the feathering propeller into feathering position and output-shaft stops from rotating. After this operation put the control lever back into neutral or remain reverse position as you like.

Notice:
Do above mentioned operations with a boat speed

Hydraulic gearbox moving in tow or sailing

When the boat moves in tow or is sailing, the propeller may turn with the water current. This represents no danger for the transmission.

When the engine is off, the position of the shifting lever is irrelevant.

WARNING:

Do not work on the transmission when being towed, or anchoring in a river because the propeller may rotate.