How to change oil in Briggs & Stratton lawnmower engine?

[kand]

Hi, first-timer here. 

I thought I had prepared myself for changing the oil in my lawnmower engine. I bought new oil and the oil removal kit made by Briggs & Stratton from Bunnings during the week and I went to do the job yesterday. 

When I put the plastic suction tube into the oil filler, there was no visible oil. Interesting that my wife had told me last week that she had checked the oil, because she was having difficulty with keeping the engine running. No mention that there was no oil in the engine! Anyway, I digress. 

When I pushed the suction tube to the bottom of the engine (crankcase?) what I felt was not a solid metal plate. It felt very soft but not like something that was made of foam like a filter. Is it likely to be a buildup of sludge? And if it is sludge, without pulling the engine down, is there a way to remove that sludge from the engine? 

Thanks for any help you can give me!

[Noyade]

Afternoon @kand 

"No mention that there was no oil in the engine!"

Any idea when there was oil in the motor?

And there's nothing on the dipstick?

I must admit to being very ignorant of combustion engines - I didn't know you 'suck' the oil out these days?

I still run my mower till it's just warm then undo the sump drain at the bottom hoping there is a quick draining process that flushes the sediment away.

Is it worth refilling your motor with oil and seeing how it goes, then check the colour of the dipstick. If still dirty maybe repeat the oil change?

Just a thought.

Cheers.

[JacobZ]

Hi @kand,

Thank you for your question and welcome to the Bunnings Workshop community, it is fantastic to have you with us.

I'd suggest grabbing some Valvoline 350ml Engine Flush, adding it to the oil reservoir following the manufacturer's instructions and allowing the engine to heat up to running temperature. 

Once at running temperature, turn the mower off and then wait for around 5 minutes for things to cool slightly. This additive should have reduced the viscosity of the oil and sludge which will then allow you to drain it using the Briggs & Stratton Oil Removal Kit.

Once drained, you can replace the oil filter and add new oil.

Let me know if you have any further questions or need some clarification.

Jacob