Petrol mower 'blowing'

[10monty]

Not sure this is the right forum but wondering if anyone can tell me what the problem with my petrol lawnmower is from the video posted. It's been like this since I got it so I figured it was normal but my neighbour has a similar one that runs smoothly.
It works fine and has never cut out but jyst doesn't sound right. I know nothing about engines!

 

[scbk]

Did you buy it new or used? Sounds like the air/fuel mix isn't quite right. Could be dirt in the carb/fuel line/fuel filter. Choke sticking partially on. Or carb needing adjusted

 

[Burnerman]

This is a Briggs engine in a Mountfield frame, I think.
These carburettors are non adjustable and one of the crudest around......it doesn't even have a pilot jet that's removable.
The hunting you experience is the engine governor speeding up and down and it often can't be stopped.
In other words, best live with it but gentle bending of the arm that the throttle cable can help - although it speeds the engine up a little.
John

 

[ellal]

I had a similar problem 5/6 years ago which Burnerman diagnosed as the carb/filter diaphragm.
Bought an unbranded replacement online for £8 which cured it, and it's still going strong.

 

[Burnerman]

I think that one might have been the engine with the fuel tank below the carburettor.....no matter, ethanol in fuel is creating havoc with diaphragms and fuel tubes!
John

 

[ellal]

Yes it was that type. And as I say, still going strong.

A neighbour had a similar engine model/problem, and (with a look of 'great knowledge') I suggested the same fix.
So you helped someone else without knowing it