Mountfield chains

[minimutly]

Now, before anyone else says this - this is a cheap pile of rubbish, but, it's not worn out, and aside from making the back of my left hand index finger bleed every time I pull it, when cold it works fine.
So, starts fine when cold, but gradually fails to take throttle more and more as it gets hotter. To the point it will only start (and run) on choke.
So is this a carb issue, or crank seals? Or something else deep inside a chinese 2 stroke pos?
I hate to bin something without trying, but a full engine rebuild is not going to happen.

 

[gaz1]

could be a simple problem heres the briggs and straton reference

 

[frank horton]

more info and a photo of the machine may help.......

Also stop using the cheapo petrol......only a few pence more per ltr but the top grade fuel make ALL machines run n start better........
been fixing this garden xrap for years.......

 

[mtt.tr]

Could be tank vent leading to vapour lock
Impulse pipe
Carb one way valve
Or hole in fuel pipe in tank


They would be were i would start

 

[rtcosic]

Also stop using the cheapo petrol......only a few pence more per ltr but the top grade fuel make ALL machines run n start better........

Please tell me where I can buy this cheapo petrol of which you speak? As I used to make the stuff and know what goes into it, I have always bought it from whichever supermarket is selling it cheapest - usually ASDA locally.


(Unless you are unfortunate enough to live in the South East and gets lots of it imported from ARA, then I feel sorry for you)

 

[minimutly]

Oops, should have been chainSAW...
Anyway, thanks @mtt.tr For those suggestions. It has a walbro badged carb Fwiw.

I have checked for tank not venting.
Impulse pipe feeds petrol to the carb - well I can pump that and it doesn't help, so unlikely? And anyway, it runs on choke.
One way valve? Will need to look for this
Hole in fuel pipe in tank, hmmm, why does it work fine cold then?

The thing will have one last chance, it makes my finger bleed every time I use it, you have to pull it with one finger on the choke, which spins the chain when it starts - it's defo a dodgy thing to do. I was thinking there may be a waxstat type mixture control somewhere, but do these things have them?

 

[Matchless]

if it was a vintage motorcycle I would say magneto condenser, they play up when hot and a weak spark likes a rich mixture to run, and I would second the comment about "cheap" petrol, only use super or whatever they call it in your local, less or no ethanol and the catalyst they use to allow it to mix with hydrocarbon, nasty stuff,

 

[mtt.tr]

Personally i would expect it to be a vapour lock


I said the holed fuel pipe as hot would assume lower fuel level