Mountfield hunting/stalling

[Bat135]

Hi

I have a really annoying issue with my Mountfield sp421 pdr roller mower.

It starts and runs fine but when it tries to hunt using the automatic choke that’s spring operated it stalls. It’s almost as if the hunting spring mechanism hits resistance and doesn’t settle or correct itself. It just moves to adjust the chicken then stops in one position stalling the engine. It moves freely with my finger?

I have changed the carb to a brand new one and still the same issue?

So it’s something to do with the automatic hunting / choke mechanism.

Any ideas? It’s doing my head in.

Kind regards. Paul.

 

[Auto Doc's]

Hi Paul,

Sounds like you are describing the governor on the engine reacting to a carburetor issue. The carburetor likely needs to be removed and properly cleaned.

Also check the fuel tank at the fuel line connection for a small pencil filter to be shoved into it. The filters exist and many people do not know they are even there. The filter screen is very fine and it gets stuffed up with sediment over time and need to be removed and cleaned.

If you are not mechanically inclined, I suggest you search for a good mower shop or mechanic that knows their way around equipment. These machines can easily hurt someone very quickly.