I installed a 4x2" circular paper air filter in place of the tractor style one on my M25XP. I noticed excessive black smoke, more vibrations at low RPMs and it even stalled once. Upon investigation I found that the air filter was black on the outside. We've put less than 20 hours on the motor this season. What are some potential sources for this much dirt? A quick inspection of the area around the filter didn't reveal anything out of the ordinary. PCV is vented inside the air filter housing. Inside of the filter looks pretty clean. I'd like to solve this issue before destroying a new filter.
New air filter completely clogged in under 20 hours!?
- Thread starter Project_Mayhem
- Start date
That thought crossed my mind. If that is the cause, would it be dirtier on the side that faces the belt? It's a strong contender as I believe I've seen some belt dust in other areas
Another idea is that the old exhaust hoses might be leaking but I'd imagine there'd be some water along with it.
I ordered a new filter so I could do some destructive investigation on the old one. Does anyone know any good tricks to help identify the type of dirt?
Another idea is that the old exhaust hoses might be leaking but I'd imagine there'd be some water along with it.
I ordered a new filter so I could do some destructive investigation on the old one. Does anyone know any good tricks to help identify the type of dirt?
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Well. I looked at the engine and the filter. The old filter that came with most engines used a reusable polyurethane coarse foam filter. But it appears you replaced it with a paper filter as you stated. Which in a high humidity enviornment such as in a boat could make dust, soot, or other particulates stick more readily on it. Not only that but a near wet filter also stops air from getting through it. Did you adapt the filter from just any filter that would fit or was this an alternative that a company said it could be compatiable.
Most engines have a tractor style filter that contains what is essentially steel wool but they likely came with a foam filter over that as you stated. The metal filter media in mine was nearing the end of its life. This meant that there was a risk of this metal getting into the engine.
I designed and 3D printed an adapter for the filter. I plan on replacing the paper one with a K&N style filter once this issue is resolved. People are using these filters on single barrel carb v8 classic cars, air compressors, motorcycles, air compressors etc. It has more surface area than the original filter with a bunch of tiny holes in it. There was no noticeable performance difference when I first installed the filter.
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 24,797
When I read "Paper Filter", my first thought was a bad idea.
Our diesel engines are simple machines. Feed them AIR, Clean diesel, and maintain compression - they are happy to propel you anywhere you please.
Dish the paper filter and look for something that lets more air get to your engine.
Our diesel engines are simple machines. Feed them AIR, Clean diesel, and maintain compression - they are happy to propel you anywhere you please.
Dish the paper filter and look for something that lets more air get to your engine.
I will be switching to a K&N filter but unless this issue is solved, it will quickly become clogged as well. IIRC, a clogged gauze filter has more restriction than a clogged paper filter
That was my reaction too. Neither of our last two boat engine had any filter on the intake as a well maintained engine should not generate any particulates.
Of all the options of filter media, e.g., paper, fabric foam, etc…, a small paper filter is to most restrictive having the least surface area and the least porosity making it the most undesirable
It vents inside of the filter housing. To my surprise, the inside was fairly clean. No obvious oil staining on the filter
Got a cheap microscope from a child's science kit.
I expect belt dust would look fibrous whereas garden variety dirt is granual in appearance. I knew I should have taken a few courses in belt dust back in the day but "meh" water under the bridge now.
Is it possible the black is mold from damp paper in a warm environment? Just switch to the K&N-style oiled cotton gauze filter. If the problem persists, then look for a cause.
I thought just what Ralph did.
It doesn't matter what side the dirt is or isn't on, since your filter is up higher and centered to starboard than the belt which is further away and lower on the port side.
Get rid of the belt dust. I did by following Maine Sail's excellent guide on shims for the alternator bracket.
I replaced my exhaust hose, it leaked lots of air but no water.
I will find out. I have a new filter arriving today. I was unable to get a good sampling of the dirt through the aluminum grate. I will take the old filter apart to find out more
This is good to know! My exhaust hoses have some cracks on them. I was planning on replacing it this winter but I think it's time to bust out a light to look for leaks!
If it is mold/mildew (or other organic material)...the black color will dissapear or turn a pale yellow or reddish color. If it is belt dust, not much will happen.
If you have any sort of spray cleaner with bleach in it.... just give the filter a squirt and see what happens. If it IS mold, clogging your filter ....then paper turns out to be the wrong material for this environment and you need to switch to a synthetic membrane.
I strongly advise not doing this. Some people get sick faster then other tougher (resistant) people just from sniffing. They could breath in pores. Those mold pores are super tiny, you won't see them in the air.
I think Pro. May. needs to do a feel test on the black stuff. Does it feel like belt or soot, or dirt, or mold. Yes black mold when rubbed in fingers does have a distinct "feel".