# Forum Home Renovation The Garden Shed  Mower Engine Oil Overfill Repair

## mojorising

I overfilled the oil on my 4 stroke mower. 
It caused the exhaust to smoke and the oil got all foamy and the engine cut out after about a minute. 
I have now drained the excess oil out of the engine and the foaminess has settled and gone back to regular coloured golden oil. 
But the mower won't start. 
The air filter is fine and dry and clean. 
I am thinking maybe the carburettor or spark plug has got drenched in oil. 
What would be the plan of action for diagnosing the problem? 
It is the Baumr-AG 720x with the 139cc engine. 
The manual is not very good and does not describe how to do engine maintenance such as carburettor or spark plug removal. 
Anybody done any work on this type of engine?

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## Bedford

Is the exhaust clear? 
Clean the plug and check spark. 
Pull over a few times with plug out then replace. 
Take air cleaner off, give it a squirt with Start ya Bastard, pull it over and tell us what happens.

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## Gooner

> Take air cleaner off, give it a squirt with Start ya Bastard, pull it over and tell us what happens.

  I had to look whether this was really some kind of product.. and yes it is. Great name. May have to buy a can just for decoration. 
Can you use it on people?

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## Marc

If the oil foamed, that means it was high enough for the crankshaft to "beat" the oil in a foam. Oil loses lubricating properties leading to severe damage ... and the extra pressure in the crankcase can blow the seals. Oil can get into the combustion chamber and hydrolock the piston and bend the crankshaft. Also can shear the key in the flywheel off and throw the timing by so much that it never starts. 
Besides all of the above ... it may be that just your spark plug is messed up with oil and only needs a clean.   :Smilie:

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## Bedford

> Can you use it on people?

  Might put them to sleep.

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## intertd6

There is probably a small microscopic feather of carbon across the gap of the spark plug, take the plug out and clean the gap, if the plug is oily , dip the that end into petrol & safely light and burn it, that will get rid of the oil, (you also use this method if you drown 4 stroke petrol engine in water)
inter

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## Marc

There is no need for using ether on a lawnmower. Misuse can cause more damage. A squirt of petrol is all that's needed.

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## mojorising

Thanks for the suggestions. 
I will have a crack at it tomorrow. 
Hope it is not totalled as it is brand new and never been used...  :Smilie:

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## mojorising

Went out today and without doing anything she fired up after a few pulls. Bit smoky for the first 10 minutes but then ran for an hour no worries. 
Ripper of a mower. Much more powerful than the lithium ion Baumr-AG e-Force 400 I got last year. The battery mower was lacking in power last year and then this year I went to charge it up and the battery is dead as a nail. Won't charge. This petrol machine seems to be the business. 
I had to tilt the mower at all kinds of angles to tackle the 0.5 metre high weeds and was worried the oil might foam again if the tilting dipped the crank into the oil but she was fine.

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## phild01

> Much more powerful than the lithium ion Baumr-AG e-Force 400 I got last year. The battery mower was lacking in power last year and then this year I went to charge it up and the battery is dead as a nail.

  I wouldn't expect quality batteries from that branding.

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## Marc

But Baum means tree in german! Must be good. And if you add the "AG" at the end of the name, pretending it is a german P/L, it is even better  :Smilie: , even more solid. 
In practice Baumr is more of a Bummer and AG stands for A barGain. Quality that makes Ozito look up market.

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## cyclic

> Went out today and without doing anything she fired up after a few pulls. Bit smoky for the first 10 minutes but then ran for an hour no worries. 
> Ripper of a mower. Much more powerful than the lithium ion Baumr-AG e-Force 400 I got last year. The battery mower was lacking in power last year and then this year I went to charge it up and the battery is dead as a nail. Won't charge. This petrol machine seems to be the business. 
> I had to tilt the mower at all kinds of angles to tackle the 0.5 metre high weeds and was worried the oil might foam again if the tilting dipped the crank into the oil but she was fine.

  You should never tilt a 4 stroke mower to the side.
Always tilt to the back 
i.e lift the front
otherwise oil can get into the valves and compression chamber as Marc described.

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## Marc

> You should never tilt a 4 stroke mower to the side.
> Always tilt to the back 
> i.e lift the front
> otherwise oil can get into the valves and compression chamber ...

  Unless it is a dry sump engine.  :Smilie:  https://www.vanguardpower.com/eu/en_...oil-guard.html 
Not that it is a new invention ... my AJS 500 model 1949 had a dry sump engine

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