Chipper problem, looking for advice

[njc110381]

I've been having some issues with my chipper today and wondered if anyone could give me some pointers? I have an Entec Trukloder which is getting on a bit now but has always been really reliable for me. It smokes a bit on start up but apart from that it's been faultless for the five or so years I've had it.

 

Well today was no different really. It still runs fine but I could smell petrol fumes coming from the machine, quite strong too. I checked it over and it was throwing petrol down the front of the engine and over the starter housing (it's a Briggs and Stratton 18hp pull start model). I shut it down and on closer inspection the petrol is running out of a small breather that runs from the carb. I took the air filter off and it looks like it's there to stop the carb from over filling with fuel? It also looks like the little nipple on the outside should have some sort of return pipe fitted to it to return the unwanted fuel to the tank but there isn't anywhere I can see that it should connect to?

 

I tried fitting a pipe to the breather but as soon as the fuel is stopped from coming out it stalls, I assume through over fuelling?

 

Why has it started doing this all of a sudden? It's always been fine for me and has been fairly well looked after in the time I've had it. In fact it's just had an oil change, blade sharpen and a new anvil! I don't use it often which is lucky, so I've got a bit of time to play with it if I have to.

 

I'd be really grateful if anyone could give me some clues as to why it may be doing this? It still runs fine at tickover and flat out, it's just throwing a steady flow of petrol out at the same time!