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K&N air filter for a 318

1194 Views 9 Replies 10 Participants Last post by  wfburton159
Does anyone out there know if there is a K&N replacement filter for a 318 with an Onan P218 engine? I need to replace my air filter and though I should just do this once. I have been digging around trying to find a direct replacement and have come up empty handed.

I have found a part number that I think might work K&N part number 4425 is 7.75 od, 6.375 id, and is 2.188 high.

From what I have found it seems that the stock filter is 8.25, od 6.375 id, and is 2.25 high. There seems to be a few different height filters listed as P218 replacements.

So it seems that my replacement might get the job done, I was just curious to know it anyone knows a K&N part number guaranteed to fit.

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Others may disagree with me but, I don't think there would be increased performance if you did install a K&N filter. The stock air filter will provide more than enough air to a stock engine. Now if you have a highly modified engine for pulling that it may help !!

Personally, I wouldn't waste my money !!
Click on search in the Yellow tool bar near the top of the page and search for K&N. You will get a full page of threads like this one.


I wouldnt do it. K&N filters dont filter as well as a regular paper filter...and as dirty as those Onan filters can get, there is NO way I would run one in there, even though I do on my bike and in my truck. But then I dont mow or plow with either one of them!
I agree with Jim on a tractor engine protection is far more important than a slight decrease in air flow resistance, the environment the tractor runs in is a lot dirtier than the environment a car runs in. I just changed the air filters in the 317 and my Dodge Magnum after about a year of use, the 317's filter was really loaded but the car filter was just starting to darken up and the 317 only mows grass in the summer.
i wouldn't do it either guy. k&n sure do look pretty and thats about all they are good for. i used them back in the late 80's for a short time on a couple 5.0 mustangs. ya know, for all there claims and hype, i just didn't notice any performance improvement. one the 'stangs was drag raced semi regular also. and who wants to clean and re-oil the filter with k&n's products that you're gonna have to buy?
Guy - I agree with the others on this one. K&N did not make a filter for the Onan as of last year, so I would bet they still don't. There might be something that is physically close, but this that does not mean it will work. - Dave
+1 for factory paper filter. K&N may help a tuned OHV, you likely won't notice the difference on a side-valve Kohler.

My $0.02 is to spend the $$ on a good steering wheel spinner knob or some other accessory.
Hi, Guy's I have a 49 snowthrow on my 425 AWS. When blowing snow the auger blows snow out the front on the side that is on the side that has been blow. It dose not make a different if I take a full cut or half a cut or how deep the snow is. I checked the auger size with a new one it the same. I have about 3/4 to1 inch from auger to housing. I have not checked other blowers to see what there are for spacing

Thank You
Rod in MN
All the single stage throwers are the same. They will do that if you take a half cut. They work the best if it takes a full cut and keep your speed up. Depends on how deep the snow is too. Sometimes you have to go back and clean up that part.
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