RUNNING REPAIRS 4 3 1 Lift pump


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2 ■ Ensure the tank has plenty of fuel in it and its shut-off valve is open.


■ Try the lift pump’s operating handle to see if it works fully. If it doesn’t work at all or seems limited, give the engine half a turn (to move the operating cam) and try again.


■ If the fuel is drawn from the bottom of the tank and the pre-filter (1) is below the level of the fuel, crack open the bleed screw and it will fill by gravity. If not, keep the bleed screw closed – it’s time to use the lift pump and turn your attention to the fine filter.


■ Open the bleed screw on the fine filter (2) and pump away until bubble-free fuel emerges. Don’t be astonished if this takes some time. When satisfied, nip up the bleed screw.


This should be enough for most engines, but not for all, including the GM series Yanmars, Perkins, Thorneycrofts and the various Kubota derivatives.


■ For them, the next step is the injection pump (3). Loosen its bleed screw (some older rotary injection pumps have two bleed screws and you will have to do both, starting with the lower one) and rejoin your labours on the lift pump. Once the fuel runs clear, close the screw (or screws) and give the lift pump a few more strokes for good measure.


This really should be enough. Try and start the engine in the normal way. If you fail you will have to bleed the injectors. Since these are on the high pressure side of the injection pump, the manual lift pump won’t be up to the task, so you will need to use the engine.


■ Loosen all the injection pump nuts at the injectors (4) a couple of turns.


■ Set the throttle to full ahead, out of gear, and turn the engine over with the ignition key. Limit yourself to no more than 15 second bursts to avoid burning out the starter motor.


■ First you will see the inevitable bubbles around the nuts, but these will become squirts. At which time, harden down the injector nuts and … start the engine!


RYA Seamanship for Sea Anglers


97


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