Yanmar 2GM Air Intake Silencer
Clean fuel and clean air are the golden ingredients for a reliable marine diesel engine. And while the marine environment can be one that offers real challenges to storing and supplying of clean fuel, clean air is surely in abundance. This is especially true when you compare your sailboat to the average construction site or farm where many small diesel engines live their life.
For these reasons, the air “filter” in the Yanmar GM engines is more of an air intake silencer than a pure air filter. Yanmar recommend cleaning or replacing this every 250 hours of use.
Nevertheless, we certainly don’t want flakes of paint, insulating foam and drips of water being drawn into the air intake. The fact that the “filter” is made of foam rather than paper or wet-oil types simplifies the design while allowing plenty of air through, but Yanmar owners often complain that the foam used in the OEM part has a tendency to disintegrate over a few seasons so take time to carefully inspect it each year. This is especially infuriating to owners as bits of the disintegrating foam will be drawn straight into the cylinders during operation.
Remove the air intake silencer housing from the engine
Unsnap the filter canister retaining clip (B in the diagram) and remove the canister and filter element.
If the canister is rusted as they often are, take the opportunity to sand it back a little and spray it with grey paint. Yanmar grey spray paint can be picked up quite reasonably in many places.
Separate the filter canister from the air intake pipe.
The canister should come away from the engine leaving the air intake pipe in place. If you are leaving this separated for a while, cover the air intake with a plastic food bag.
Remove the foam cone from the canister and inspect the foam for any physical damage or signs of disintegration (as mentioned above). Discard if damaged in any way.
Wash the foam
Clean the foam cone and mesh in warm soapy water. Many owners report that washing the foam can cause the disintegration mentioned above. Again, if it cannot be cleaned or gets damaged in the process, discard and replace.
When the filter is clean, if the foam filter is still intact then thoroughly dry it.
Reinstall the filter and canister
NOTE: When reattaching the canister to the engine, make sure that the air intake points slightly downwards. Otherwise, water could enter the filter and from there be sucked into the engine.
TECHNICAL DETAIL: Yanmar Part Numbers
- 128270-12500 Air Intake Silencer
- 128270-12540 Air Filter
- 128270-12700 Air Intake Pipe
- 22117-060000 Washer 6
- 26013-060142 Bolt M6 X 14
- 26106-080182 Bolt M8 X 18 (PLATED)