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k1vsk 12-23-2006 02:01 PM

Yanmar 4JH air filter
First question:
I'm wondering if anyone with a 4JH has an air filter on their engine intake?
Some of the other Yanmars have filters but mine does not. Both the engine and service manuals indicate the location of the silencer where a filter would normally be. From these, it would appear that Yanmar didn't intend for a filter which doesn't make sense - I wouldn't expect lots of dust in the engine intake but it is possible for debris, belt dust, bugs, etc to enter.
Second question:
If I were to install a high capacity filter, would there be any long-term affect of restricting air flow to the engine.

RichH 12-23-2006 02:48 PM

Most of what you see on marine diesels are not filters but 'silencers'. Even in the middle of the ocean, air is 'dirty' and containes a lot of hard submicronic particulate - especially if there is a desert or volcano upwind. Does this affect the service life of an engine ... probably not as these particles are extremely small and approach being 'harmless' to the engine as they contain little inertia / mass once inside. If you are keen to actually put a FILTER on the engine you can apply 'retro-fits' such as the dry paper elements from such manufacturers as "K&N", etc. ... just be sure to well 'oversize' the filter ... based on 'cubic ft. per miniute' of volumetric aspiration of the engine at 'wide open throttle'. Forget about 'wet' or oil-bath filters as they are essentially 'worthless'.

Giulietta 12-23-2006 03:19 PM


Just called ther Yanmar Importer over here and asked him the question.

I Have a 3JH4E, and they all must have an air filter.
It's a chicane type filter, and is a plastic box located on transmission side satarbord side.

He said its not urgent, but recommends you put one.

Can't post thwe photo, unfortunately. I have one if you PM me I can send it to you.

k1vsk 12-23-2006 03:48 PM

Thanks guys.
I just checked the Yanmar service manual for the 1GM, 2GM and 3 GM/3HM engines and they too show only the silencer. It seems strange to me that only some (one?) Yanmar would have an air filter.
Regardless, I appreciate your responses and will check further on what kind of restriction the engine can tolerate.

billangiep 12-23-2006 05:21 PM

For Yanmar silencer and silencer elements.... Parts catalogs for Yanmars and most other diesel engines. I just perchased two elements for my Yanmar 3GMD for around $14.00 each.

Giulietta 12-23-2006 05:22 PM

Are you talking about Silencers or Air filters??

I thought he lacks an air filter.

billangiep 12-23-2006 05:42 PM

The silencer has an air filter in it. Yanmar just calls them silencer elements.

k1vsk 12-23-2006 06:04 PM

The silencer in both my 4JH and that of my son's 2GM20 is hollow - no filter! The silencer itself won't filter a baseball!

billangiep 12-23-2006 06:20 PM

Yanmar makes a cone shaped air filter (silencer element) that fits inside the silencer. My past 2GM had the same filter silencer as my present 3GMD.

billangiep 12-23-2006 06:29 PM

Air filter (silencer) photo and part # 128170-12540</B>Air Intake Silencer ElementAdd to Cart117.74

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