50:1 petrol mix ok to run in a lawn mower?

[AlvinD]

Hi guys as the title says, is it ok to run 50:1 mixed petrol in a lawn mower that takes straight petrol? Thanks

[Nick B]

If I have any stale or old 50:1 mix I put it in my mowers.

not done any harm so far, I would not run them on it all the time.

[Coletti]

My old man has done it for over 10 years with ours whenever he runs out of strait petrol so I'm going to say yes. It's just a little more lubrication using mix so can't see it hurting

[doobin]

Can foul the plug a bit, but I do it if we run out or we find a can of mix which is a bit old to run through a saw.

[AlvinD]

Thanks. It's my dad's 33year old lawn mower and didn't want to wreck it on him. There's about a third of a tank of straight in it so I'm happy enough to go ahead

[MrHairy]

My old Mountfield Empress seems to run better when I use 50:1

 

Another newer Mountfield I have seems to run a little slower and smokier with 50:1

[TimberCutterDartmoor]

A little upper cylinder lubricant is a treat for it but can cause plug fouling, not an issue in the short term...

[spudulike]

Plug fouling, smoke on the garden (Deep Purple) and oil dripping down the air filter but it does get rid of stale petrol/oil mix:thumbup:

[predator]

i use it in my old mower all the time done so for years

[GardenKit]

The odd accidental filling wont hurt at all, as others have said, it will just be a bit smokey.

 

But its certainly no treat for the upper cylinder, which does just fine on the standard lube past the rings.

Frequent use of 50:1 will not only foul the plug, but also build up a thick layer of soft, black oil deposit on the piston crown and around the swirl chamber. This will raise the compression and lower the combustion efficiency.

 

The exhaust muffler will also clag up in time.