# Oi leak MTD 990 brush cutter, through air filter



## sobo (Aug 25, 2012)

Hello,

I purchased a MTD 990 brush cutter, 4 strokes, serial 41AD990C678 images.agroterra. co.uk/1823_I_aki41.jpg. I noticed that even without using it, the brush cutter will leak oil through a black tube that connects the motor body to the plastic air filter holder, picture here img826.imageshack. us/img826/1889/dsc01267k.jpg

I disassembled the air filter plastic holder, cleaned completely the pieces with detergent as per the fabricant's instructions. Oiled the air filter. Left it standing without trying to turn it on. No way. After some time the whole equipment is covered with oil that leaks from the black tube, it is a mess. I found the spare part list and exploded vision for the MTD 990 but could not find the code or name of this black tube or if this oil leak is normal or not (the air filter must be oiled, but actually it is being "submerged" in the oil that leaks from the black tube). 

Any trick, advice is welcome on how to solve this oil leak issue


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## usmcgrunt (Sep 16, 2007)

Hello and Welcome to Hobby Talk.That rubber hose is a breather hose that routes oil vapor to the intake so it can be burned and not released to the atmosphere causing pollution.
Have you checked the oil level in the crankcase?The owners manual should tell you the capacity.I have an MTD 4 cycle string trimmer that requires 3 ounces of oil in the crankcase.I would drain the oil and refill with the correct amount stated in the owners manual and see if it corrects the problem.
Hope this helps.


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## Morella (Aug 15, 2012)

I always look to the simple stuff. If this is happening while the engine is not running, make sure that you're storing it so that the oil sump is at the bottom. Otherwise, oil can seep in through that breather tube. If oil is coming in while it's running, that's a more serious problem. Could be overfilled too.


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## Rentahusband (Aug 25, 2008)

I agree with Morella.


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## sobo (Aug 25, 2012)

*Thank you*

Thank you usmcgrunt and Morella. The crankcase was overfilled with oil. I did as you advised, and with 30oz it will not leak anymore. Do not find where to attribute you 5 stars or points for your advice.


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## usmcgrunt (Sep 16, 2007)

Sobo,glad to hear that it was a simple no cost fix.I'm sure you meant (3) ounces of oil, 30 ounces would not fit. There is no point system,our rewards are learning that the information given helps you correct the problem you had.Thanks for posting a positive reply.:thumbsup:


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