Ariens Oil Blowback into Air Cleaner

Tejass

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Nov 28, 2016
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I've got an Ariens 911014 push mower (21") with a 5 hp motor. The problem is it blows oil back up into the air cleaner.

It's my deceased father-in-law's that was given to my son. I'd like to keep it going for the boy, but not sure what to do to fix it. I understand from the Ariens web site that it could be:

•Too much oil in crankcase - check dipstick for proper level
•Engine speed is too excessive
•Oil fill cap or gasket is damaged or missing
•Breather mechanism is dirty or defective
•Piston ring gaps are aligned
•Piston rings are worn

It also sounds like it might have a slight knock. I hoping this sound is the sound made by the blowback issue.

I have changed the head gasket and rebuilt the carb when he got it. I'm not sure if he ran it low on oil or what.

It starts right up with one or two pulls. Any thoughts or guidance on the diagnosis?

Thank you in advance.
 

upupandaway

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Jul 3, 2015
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I have seen a few Tecumseh motors where rings went bad- aluminum and iron blocks so slight maybe it is also leading to your problem.

I had a Briggs with exactly your problem. When running, do u hear a solid metal hitting metal or small ticking noises? On cars and on mine- the noise was solid enough metal hitting metal/piston slap (piston or cylinder worn out - mine cylinder).
Easiest way to confirm, take the cyl head off and push the left and right side of the piston if horizontal to see if there is play. play=wear. Also move piston to BDC and look at the cyl wall if hatchings are gone, potentially cyl too out of round.

If you want to try the easier route first, replace the breather valve\PCV.
 

Tejass

Forum Newbie
Joined
Nov 28, 2016
Threads
2
Messages
4
I have seen a few Tecumseh motors where rings went bad- aluminum and iron blocks so slight maybe it is also leading to your problem.

I had a Briggs with exactly your problem. When running, do u hear a solid metal hitting metal or small ticking noises? On cars and on mine- the noise was solid enough metal hitting metal/piston slap (piston or cylinder worn out - mine cylinder).
Easiest way to confirm, take the cyl head off and push the left and right side of the piston if horizontal to see if there is play. play=wear. Also move piston to BDC and look at the cyl wall if hatchings are gone, potentially cyl too out of round.

If you want to try the easier route first, replace the breather valve\PCV.

Thank you. I've told my son to plan on buying another one this coming season. I appreciate the info!
 
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