Rotavator Problems

[reddwarf30]

Hi all, this is my first post as a newbie hope its the right section..Just bought a merry tiller rotavator 20+ years old but all in good nick, trouble is it starts first pull every time but when you try to rev it it keeps cutting out, i have had the air filter off to expose the carb and there is a part on top which has a couple of springs on it this keeps opening and shuts the engine down (hope thats clear..I can send pics perhaps) Doing my head in now I have had it running perfectly but now it seems the choke system is not balanced any ideas PLEASE!!!!

[brooklyn1]

If it starts easily but cuts off on revving the first thing I'd check is for blockage in the fuel line (make sure it's not pinched), could be as simple as schmutz in the fuel tank, or crap in the carborator. And make sure you're using fresh petrol, and that it's clean... typically small gardening machines don't have fuel filters, get a gas can that has a spout filter, or at least pour through a fine mesh sieve (there are such fuel funnels). Sometimes there's a clear priming bulb, look carefully for crud and/or water. I would drain all the fuel, flush the fuel system with fresh clean fuel and then refill with fresh clean fuel... be sure your petrol can is clean too. With a newly acquired used machine I'd change the crankcase oil, and install a new air cleaner, may as well a new spark plug while you're at it. If it starts easily there's likely nothing seriously wrong. Good luck with your machine, and be safe.