Hello from sunny Cheshire UK!

[Sallyday10]

Lots of reasons why the purge bulb will not fill.
If it pops back quickly the suspect a broken fuel line
If it does not seem to want to pop back suspect a blocked fuel filter in the tank/ blocked internal fuel filter / stuck check valve

Thanks Berty,

where is the check valve located please?

Mike.

 

[bertsmobile1]

There can be 3 of them depending upon the actual carb
One or two will be in the purge valve housing which control fuel flow through the card, back to th e tank and the pressure in the tank
The third is in the body of the carb and unlike the purge valve housing is not replaceable, it controls the fuel flow through the main jet .
Walbro & Zama Both have fairly good service manuals on their respective web pages with good colour coded diagrams explaining fuel & air flow through the carb .
There are really only 2 types of cube carbs butterfly & rotary valve so either manual will point you in the right direction.
I used to put links into posts to them but 99% of the people who posted a problem just want it fixed and don't care about understanding what they are doing so I gave up.

 

[Sallyday10]

There can be 3 of them depending upon the actual carb
One or two will be in the purge valve housing which control fuel flow through the card, back to th e tank and the pressure in the tank
The third is in the body of the carb and unlike the purge valve housing is not replaceable, it controls the fuel flow through the main jet .
Walbro & Zama Both have fairly good service manuals on their respective web pages with good colour coded diagrams explaining fuel & air flow through the carb .
There are really only 2 types of cube carbs butterfly & rotary valve so either manual will point you in the right direction.
I used to put links into posts to them but 99% of the people who posted a problem just want it fixed and don't care about understanding what they are doing so I gave up.

Thanks Bert,

I appreciate your help.

I'm keen to know a little more about the carbs on these units, do you know if there's a simple way of identifying the model/type that I have?

Thanks,

Mike.

 

[bertsmobile1]

The brand is generally cast into one of the covers and they all have numbers etched or stamped into the sides.
Hidden right down in the bottom right corner of the Walbro page is the link to the service manuals and a couple of videos that you might like to watch.
Zama also have the same information on their Technical Help drop down sub menu from the "support " link in the navigation bar on the top of the page .
Hidden some where on the Zama page is a cross refference which lists which Zama carb is the OEM or a direct swap for a lot of hand held equipment .
I should book mark it cause I can never find it when I need to .
Zama & Walbro are the biggies
Ruzing have become very popular because they have no technical support which forces the owner to take the tool back to the shop for repairs & makes it difficult for people like me.
Top end stuff with have a TK from Japan or a Tillotsen from Ireland