445 spark plugs with black deposits

[srsvii]

My 445 Kawasaki engine powered JD seemed to begin to leave a black sooty deposit on the spark plugs. I checked because when I actuated the deck PTO the exhaust gave a big dark puff like it was too rich a fuel mix. This happened for a while when I decided to check the plugs and saw the sooty deposit. I have changed the plugs and installed a new air filter and used it for two hours where it ran well and didn't seem to have the same very dark exhaust when the PTO was turned on but I'm not sure if it is really fixed.

The engine has 2500 hrs. on it and I wonder if this is something bad beginning? What might it be if it is not the simple air cleaner/new plugs fix? Could it be a problem in the efi system? If so what might it be?

Thanks for any learned advice to help me out here.

Enjoy your weekend folks, it should be nice.

 

[flyerdan]

If the air filter was really dirty, it could cause an over rich condition that would leave black sooty deposits on the plugs and black exhaust smoke from unburned fuel. If it can breathe again the power level should go up and the plugs should show the normal beige color. If it's burning oil there should be some blue smoke from the exhaust and the plugs will have a black oily deposit. Google spark plug diagnostic images and find one close to what you see and follow that link for fixes.

 

[srsvii]

Thanks Flyerdan for the info. I believe that oil is not the culprit and you hit the dirty air filter on the nose causing the dry, sooty condition of the plugs. When I can do a complete property mowing, five hours or a bit longer and then see the performance and check the plugs when the tractor cools I will have better chance to make a correct diagnosis. I hope I see the beige/tan burn you describe but with the advanced hours I wondered if I was finally hitting the dreadedd "mowing of no return"!!!

 

[flyerdan]

It was probably the clogged air filter. If you routinely mow in conditions that create a lot of dust, it might be worthwhile to see if you can get a washable filter, like a K&N. If not, I'd clean it with a shop vac or carefully blow it out from the inside with compressed air. Every filter maker says not to do that, but then, they want you to buy another one of their filters.

 

[Kish318420]

Can you get a washable foam pre-filter that you can change before. That is what I do on my onan powered 318 and 420. Of course I have to re-apply some oil and squeeze it evenly into the filter.

 

[srsvii]

Yes, I've been using the foam pre filter but getting the oil applied thin and evenly across the entire foam filter is a challenge. What kind of oil do you use on the foam element?

 

[Kish318420]

I usually wear gloves, the type like doctors or nurses wear when working with product that can cause skin contact issues. I also have a cheap little oiler with pump (can be found in any auto parts, lowes, home depot, ace, etc) and apply 3 to 4 thin ribbons of oil to the foam filter (outside part) and then work it into the foam (squeezing by hand) then remove any excess with paper towel again squeezing the filter with paper towel.
I have like 4 foam filter that I rotate. I use what ever I have emptied out of the quart containers after oil changes (drippings). Usually a mix of 5W-30, 10W-30, 10W - 40, SAE 30, SAE 40, 5W - 40.

 

[srsvii]

Thank you for the detailed reply. It gives me new insight into the whole process.

 

[RandyT]

Latest recommendations from the engine manufacturers is to not oil the foam wrap filter. Due to the over oiling of the foam, and then it seeps into the paper filter clogging the media. Oil of foam only filters like what is used on some push mower engines is still required, but the oiling of the foam over a paper filter is not recommended at this time.

 

[srsvii]

Thanks For the update. I makes sense to me as it was so difficult to get the correct amount of oil dispersed upon the foam element. I actually did what you suggested and did not oil it this last time when installing the new air cleaner element. Again, until I have several more hours on the unit I won't be able to tell the outcome but so far, after two hours it was running quite well. This makes me think I had messed up the paper element with the oil issue in the past. The old rule of thumb was to look through the paper element against a light or sunlight and if you could see light through the element it was clean enough to continue using. I did see some darker spots in the old paper unit that I discarded.