For the voyager, a good tender with a reliable outboard engine is essential gear. Outboards do raise some issues, however. While the majority of sailboats have diesel auxiliary engines, outboards tend to be gas-powered. This means storing and using a second, incompatible fuel type. And with their spark plug-driven gas engines, outboards require a different set of troubleshooting skills than those needed for a diesel engine.
There is also the task of handling and securing an outboard at night and while on a passage, when it can’t be left on a vessel’s tender. With any motor larger than four hp, you will need help to lower it down or lift it off the dinghy. Several companies make neat davits that you can mount along the stern pushpit. They work with a purchase and a harness that take the weight off your own back. Of course, you can rig a mizzen or mainboom with a purchase to lower the motor into the dinghy. And for the nightly routine you can simply use the spinnaker halyard and winch to lift the dinghy with the motor attached and leave it hanging alongside the hull or resting on deck.
Traditional davits over the stern work fine in coastal cruising. For blue-water sailing you will have to take the engine off even if you leave the dinghy on the davits. Except on very large yachts (longer than 90 feet LOA), as soon as the boat heels over in any significant sea state part of the dinghy will hit the water. I had it happen on a beamy 72-footer with considerable freeboard. On another, a classic 68-footer with moderate freeboard and beam, the dinghy on the stern davits would slam hard each time the bow rose up on a wave. Take the engine off, and the whole set-up may just last a little longer. For an extended ocean passage you should deflate the dinghy and stow it on deck.Keep it running
An outboard motor needs a mixture of fuel, air, electrical spark, and compression in order to function. On occasion one of these elements goes astray, forcing you to do basic troubleshooting. The following are some typical illnesses even new engines can develop and repair procedures that require only pliers, a screwdriver with two bits, a couple of socket wrenches, a spark plug wrench, a plug gap feeler gauge, and a plug gapping tool.1. The engine refuses to start.
Is the clip of the kill switch still in place? See that there is gas in the tank, the cap air valve is open, and the primer bulb has been squeezed a few times. If the bulb does not fill with fuel, the inside check valve has failed. Position the tank on the seat above the motor’s fuel pump. Crank the motor while pumping the bulb, and once the motor fires enough of the fuel will probably flow to get you home. Engines with integral tanks have petcocks that must be open. The tank fuel strainer should be clean. The anti-siphon valve in integral tanks may get stuck. Test it by connecting an external tank to the carburetor. If the motor starts then, replace the anti-siphon valve.
When the tank fuel line and the bulb work, attach them to the motor. Open the engine cover, slip the fuel line off the fuel pump, and squeeze the primer bulb. It fuel fails to squirt out you have blockage in the fuel filter on the motor. On an engine with an in-line filter, take the filter off and run the fuel line directly to the pump. If you have a canister filter, clean the filter element. The motor should start now. If not, the fuel pump may be bad. You can test it only on an engine equipped with a remote pump. Pull the fuel line off the carburetor, crank the engine, and see if gasoline flows evenly. A pulsating flow indicates bad pump check valves or a punctured diaphragm. Integral pumps that deliver fuel directly to the body of the carburetor can only be inspected visually after dismantling the pump (see below on how to do it).
If, after all this, the engine still plays dead, check the spark plugs. Wiggle the rubber cap off the plug without yanking heavily on the high-voltage lead wire. Unscrew the spark plug and put it back into the cap. Using the rubber cap as insulation against electrical shock, ground the plug body against the block and crank the engine. A good plug should produce a visible spark. If no spark follows, examine the plug for a cracked insulator and replace. Still no start? Pull the wire out of the spark’s rubber cap, clean the spring-shaped wire at the end and reinstall. If no spark appears now, I hope you carry oars in your dinghy. In motors more than two years old, the high-voltage wire insulation may have developed cracks that allow electricity to leak from the wire. These are easy to see if you take the engine cover off and run the engine in the dark.
If you get a spark in the plug test but the engine fails to fire, you will have to drain the carburetor bowl. The draining screw in the bottom of the bowl can often be accessed through a hole in the motor housing. Do not remove the screw if the boat is in the water. The screw is difficult to reinstall and easy to lose. Instead, unscrew the carburetor silencer cowl, undo the carburetor fasteners, and take it off to work inside the boat. If dirt runs out from the bowl you will have to dismantle the carburetor for cleaning. Do it over a table or workbench and take care with the tiny parts connecting the needle valve and the float. 2. The engine dies underway.
See if the safety switch clip slipped off. Look at the propeller. It may have fouled a plastic bag, fishing line, or a floating poly rope. If the engine stopped after first sputtering, laboring and smoking, see that the choke valve has not vibrated into the closed position. If none of these apply go through the checks for No. 1 above. 3. The motor starts easily but runs rough, refuses to accelerate, and smokes.
The spark plugs have carbon deposits and are wet with fuel. Remove the carburetor and undo the reed valve holder located behind the carburetor. These plastic reed valves control the amount of air and gasoline coming into the engine, and they come in a variety of shapes. Sometimes reed gaps can be adjusted with a feeler gauge following the shop specs. Usually, though, they have to be replaced after the plastic has lost flexibility and cracked. In some models, reversing the reeds may help for a short time.4. The engine starts but will not accelerate and uses noticeably more fuel.
When you open the engine cover the smell of gasoline becomes strong. The spark plugs are wet and filled with carbon depositsthe result of flooding. Remove the carburetor and install a new needle valve and float (if damaged). After reassembly tune the carburetor by adjusting the idle speed for the lowest smooth rpm. Tighten the idle mixture screw all the way and then back it out almost two turns. After the engine has warmed up do the fine tuning on the idle mixture until the motor (in gear) accelerates without hesitation. 5. Engine starts reluctantly, runs rough, then dies.
A multi-cylinder engine may run at the high rpm setting but very roughly. If checking the fuel flow and checking the spark plugs does not help, you will have to dismantle the fuel pump. Work carefully so as not to lose the spring and its seat. Look for pinholes in the diaphragmthe usual cause of pump failures. Use new gaskets when replacing the diaphragm. On a remote pump you can test the intake and outlet check valves by blowing and sucking through the openings. After a pump breaks down underway you may get home in fits and starts by placing the fuel tank high and pumping the primer bulb. 6. The engine runs, but you hear a hissing sound after shutting down, and steam comes from the cooling water pilot hole.
The cooling system has failed and the water pump impeller must have lost several blades. And you failed, too, because the impeller breaks down gradually and you should have seen it happen. When no water runs out of the pilot hole at idle but begins to drip when you rev up, the impeller has already lost a couple of blades. Any reduction in water flow from the normal should draw your attention. Sometimes deposits in the pilot hole restrict the water flow, so try to clean the orifice with a piece of wire before getting at the water pump. On larger engines an alarm may announce overheating when the thermostat malfunctions. Run the engine with the thermostat removed to see whether it works cooler.
To replace the water pump impeller you will have to drop the gearcase in order to reach the pump mounted on the drive shaft. On some models you have to move the gear shift into neutral or reverse to reach the connector for the gear shift rods. After undoing the fasteners use a rubber mallet to tap the gearcase loose. Remove all broken impeller pieces before installing the new one, apply sealing compound to the new gaskets. Reassembly of the gearcase calls for patience since you have to realign the drive shaft, water tube, and gear shift rods. 7. The engine runs well but when you open the drain plug in the gearcase the oil appears milky.
Water got into the case. Take the engine to a mechanic who should apply five psi of air pressure to the drain hole to find the leakmost likely the seal on the propeller shaft. Let the shop do the work, which requires special tools and the application of heat to free the old seals. The motor will run with the water in the gearcase but eventually corrosion will eat the gears. 8. The motor runs but progressively the rpm hits high soprano while the boat slows down.
Very likely the rubber hub in the propeller is beginning to slip. Get a new propeller. 9. Rewind starter rope breaks.
Lift the assembly from the top of the engine after removing the starter lock-out cable, which prevents starting in gear. Working with the starter assembly be extra careful not to let the recoil spring suddenly fall out and uncoil. It can cut you and cannot be reinstalled. You will have to buy a new spring, which will arrive pre-coiled. Do not remove the ties that hold it in tension until the spring is seated and retained in its housing. The new starter rope must be cut exactly the same length as the original. While waiting for parts you can start the motor by spinning the flywheel with the emergency rope.Spark plugs tell the story
Most problems develop gradually, and you will see them coming if you occasionally remove the spark plugs. Spark plug electrodes wear out; you should inspect them every 100 hours to readjust the gap with a gap setting tool. Do not close the gap by whacking against the sail trackyou may crack the insulator. Replace the plugs every 400 hours. Look at the plugs carefully. A plug with wasted electrodes and whitish deposit build-up reveals overheating. A water-wet and very clean spark plug indicates that water enters the cylinder. Fuel-wet electrodes covered with soot and carbon point to carburetor or ignition problems. Very heavy carbon build-up on the plug means the wrong type of oil or too much good oil in the gasoline.
You can postpone the repairs by prevention. Use fresh fuel, strain it before mixing with oil, and install an external fuel filter between the tank and the engine. When you are voyaging in remote areas and are forced to carry quantities of gasoline for a long time, add storage additives. Do the same with the portable fuel tank after topping it up. Before a long ocean passage run the outboard motor in fresh water and then empty all gasoline from the carburetor to prevent the formation of gum. Buy a grease gun and regularly pump grease into all the nipples of the engine and the transom clamps. To prevent the motor vibrating loose from the dinghy and into the drink use a lanyard to back up the transom clamps.
When buying a new engine, get the dealer’s mechanic to tell you how to get at the water pump, remove and adjust the carburetor and learn any idiosyncrasies of this model. Buy spares: set of plugs, a needle valve and float, a fuel pump diaphragm and gaskets, and a water pump impeller and gaskets. Although the litany of cases above may look disconcerting, a modern, well-maintained engine will run for a couple of years without breakdowns. After that, just between you and me, sell or trade the beast for a new oneunless you enjoy tinkering with motors, in which case you should get yourself a shop manual for that engine.
Few people realize that an outboard may pay for itself when your auxiliary engine fails. Instead of coughing up bucks for a towboat, rig the dinghy with the outboard on the quarter and push the mothership to the nearest safe anchorage. We have done it when becalmed on our 10-ton, engineless 38-footer, and we can move the boat at more than three knots with a six-hp outboard. Twice we went through the Panama Canal powered by 15 hp, which pushed us effortlessly at hull speed. And a 25-hp engine will even move a 70-footer at a good clip.