Yanmar Pleasure Boat Marine Engine Help

Tips on this page:
Coolant
Cylinder head retorque
GM series injector assembly
GM series, Engine starts then dies. 'E' serial numbers only
YSB / YSE and YSM transmission removal
Recycle copper washers
Turbowash

Maintenance Stuff

Coolant: In Fresh water cooled engines the coolant must be changed in accordance with the coolant manufacturers instructions. Check HERE for important information about coolant.

Retorque at 50 hours and then every 500 to 600 hours on one and two cylinder engines, as per the Service Manual on other engines. 50 hour cylinder head retorque on 1GM10 and 2GM20 engines is not required.

N.B. Before torque loading any bolt or nut you must ensure that the nut or bolt will run freely down the thread and that the threads and contact faces are lightly oiled with engine oil.

TURBOWASH

If the engine begins to smoke while underway firstly check the hull and propeller for fouling, the injectors for condition and the turbocharger for damage. If these are all OK, TURBOWASH the turbocharger.
TURBOWASH is a genuine Yanmar part, dont let any ignorant dealer tell you otherwise. The dealer should be repacking the TURBOWASH from the large container and selling it in 250cc / 8oz bottles, not fitting you up with a lifetime supply!

• Thunder down the harbour with the engine at 75% load and spray up to 25mls of TURBOWASH into the air intake over about 15 seconds.
• Wait a bit
• Spray an equivalent amount of clean fresh water into the air intake
• If it doesnt come clean, try up to 4 times.


In some manuals Yanmar recommend using dishwashing liquid if TURBOWASH is not available. In my experience it doesnt do the job whereas TURBOWASH cleans right around the bend. I can only recommend the proper product, it really works!

GM series fuel injector assembly into the head

Item 16 Retaining nuts (10mm spanner) Item 54 Retaining clamp.
Item 55 'O'-ring, to stop water running down the side of the injector and rusting it into the head.
Item 53 Washer, copper, with small hole. Heat dissipater.
Item 52 Insulating washer (fits in a groove in the top of the pre-combustion chamber, 47) Fiber like washer for reducing the heat transfer to the injector.
Item 47 Pre-combustion chamber top half
Item 51 Copper washer
Item 48 Pre-combustion chamber lower half with Item 50 the locating pin for correct alignment.

TIP: Replace the insulating and copper washers each time the injector is removed for service.
Injector pressure is 160 kg/cm², 156.9 bar, 2275 psi or 15690 kilopascals.

Recycle copper washers

If you dont have new copper washers when you reassemble the fuel lines, and provided there are no scores across the faces of the ones you have, they can be made reusable by heating to cherry red ( with a lighter, gas burner, etc.) and quenching immediately in water.

YSB, YSE and YSM transmission removal

Take out the gearshifter mechanism, etc, from the back first. There is a shaft that extends from the flywheel through the gearbox and to the gearshift at the rear of the box. Remove the gearshift cover and undo a nut that has a split pin through it. About 19mm from memory. Then remove the bolts around the flywheel housing. Be careful when splitting the box from engine that you don't bend this shaft. (with the compliments of Alastair Donald)

'E' series only GM engine fuel return line non-return valve.

If the engine starts then dies and bleeding the fuel solves the problem, this check valve may be faulty. It could be corroded or worn. Part Number 128296-59940 and 22190-120002 Seal Washer Qty -2-

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