Confused by lack of air filter on Yanmar 4JH5X1

[a64pilot]

Originally Posted by OrangeCrush

Hoping to revive an old thread here but I'm looking for a suitable air filter as per this discussion. I called K&N to find one that would fit my 1.5" air intake hose and they said that it has to be a flame arrestor rather than an air filter as per USCG guidelines, and they don't make one that small. Does anyone know where I might find a suitable product?

There is a lot of dust and the occasional dog hair floating around my engine compartment and putting a filter on seems like wise preventative medicine. Thanks.

Did they really say that? If so I’m astonished for a couple of reasons, first the K&N is a flame arrestor, it is because of the metal mesh, filters without the metal mesh aren’t. Flame arrestors are just metal mesh. Look at how a screen is used under a Brunson burner as an example.

But what is really surprising is that a Diesel doesn’t require a flame arrestor.

I believe you got an uninformed person.

I know that a K&N is an approved flame arrestors cause back in the day we used them on high performance Jet Ski’s, and an inboard gasoline boat requires a flame arrestor.

On edit, found this with a brief Google
https://www.knfilters.com/marine/boats.htm

Then this, it’s readily apparent they are regular K&N filters
https://www.jegs.com/p/K-N/K-N-Marin...43337/10002/-1

[a64pilot]

Originally Posted by Cheechako

Filters etc are needed when road driving through dust, bugs etc. Many boats dont have any element. But they do have baffled silencers, it's very surprising how much valve noise comes through an open intake on diesels.

It’s called intake honk, and if you look a the inlet of just about any modern automobile, you’ll notice it has odd attachments to it that are just open boxes, those are resonance chambers to reduce the Honk, motorcycles have trouble meeting the noise emission requirements at times due to honk.
Harley specifically has issues cause the carb and exhaust are on the same side of the bike,I remember that cause Eric Buell’s bikes didn’t have that problem.

[Compass790]

What A64 said,
IMO any air filter is better than none.
Can see fish scales,carpet fibres,belt dust & ceramic exhaust wrap fibres stuck on the outside of our aircleaner. Surprises me that people run without aircleaners on boats but each to their own. Scares me more getting something sucked in there accidently than the contamination though.
Cant notice any intake noise on our noisy single Yanmar with or without air filter but I'm a bit deaf & can notice it on some motors. We have the same sort as post #13.
The cheap aircleaners foam glue didnt like being washed in petrol but easy to reglue with a bit of silicon.

[Seriously Slow]

I have a 4JH2E and it appears to have a filter housing with a snorkel style intake but no filter. I have asked a number of different Yanmar service and parts suppliers and the answer is the same, no filter.
It just seems wrong somehow so I decided to find one that fits.

[OrangeCrush]

Looks like this one will fit my motor's air intake: https://www.knfilters.com/62-1470-ve...ilter-breather

I check on the packing gland pretty frequently while motoring these days, and every time I lift up the pilothouse sole above the engine I end up dumping a bunch of dust and dog hair down there, so I agree that any filter is better than no filter. I think this filter will be fine assuming the following two things are true:

1) It won't increase the risk of fire compared with the 1.5" gaping hole that is there now
2) It won't impede air flow to the engine

[thinwater]

Where does the crankcase breather go. You may want to address that at the same time.

[OrangeCrush]

I'm gonna show my ignorance yet again but what is a crankcase breather and where would I look for it on my Yanmar 4JH5X1?

[Compass790]

Crankcase breather is to vent any pressure from the engine so it doesnt leak oil.
Normally you will see a small hose or pipe from the rocker cover into the air intake pipe or air filter/ intake muffler housing.
On our little Yanmar YSM8 it comes from the side of the crankcase into the air intake pipe downstream of the filter.

[Wotname]

Originally Posted by OrangeCrush

I'm gonna show my ignorance yet again but what is a crankcase breather and where would I look for it on my Yanmar 4JH5X1?

Dunno about the 4JH5X1 but here is a picture of a 4JH4AE. This and Compass790's description should be enough for you to find it on your engine!

[Spindrift NH]

Just a thought, if you have a runaway engine how would you quickly limit air to the intake with a filter assembly on it?
I too have thought there should be a filter on my intake for dust, hair, ect... but have been reluctant due to the runaway scenario.
I don’t have a noise reducer on my engine, just a pipe with a screen.

[Compass790]

Originally Posted by Spindrift NH

Just a thought, if you have a runaway engine how would you quickly limit air to the intake with a filter assembly on it?
I too have thought there should be a filter on my intake for dust, hair, ect... but have been reluctant due to the runaway scenario.
I don’t have a noise reducer on my engine, just a pipe with a screen.

Our air filter is not that tight on the air intake pipe. I don't even have a hose clamp on it but you could have one just tight enuff to yank it off if necessary.

[Spindrift NH]

Yeah, that makes sense

[Draughty]

My 30hp diesel came new 6 years ago with a plastic bodied air-cleaner with replaceable element. Given the price of a replacement element (only available from the dealer), and that I had already had to modify the air cleaner cap to stop it falling off, I chased around and discovered disposable air-cleaners; just pull off the old one and fit the new with the same hose clamp. Donaldson, Baldwin and Fleetguard list them in Oz.
Don't know how they stack-up environmentaly though.

Rgds

[OrangeCrush]

Originally Posted by Wotname

Dunno about the 4JH5X1 but here is a picture of a 4JH4AE. This and Compass790's description should be enough for you to find it on your engine!

Ah yes, thank you! That's the "other hose" I noticed on the air intake silencer box, and I guess it also explains why the box had oily residue on the inside. Since I would be putting the air filter on the large intake hose coming off that box, the crankcase breather should also be protected by doing so.

[UK Ade]

I’m about to go through the same process on my Yanmar 4JH5E engine. Identical air filter box. Did your (Orange Crush) KN Filter fit and work for you?