[Buzz343]

Good morning, I was just wondering if anybody could help me? I've recently bought a mccolloch tm300ax petrol strimmer. I bought it as spares or repairs, I got it to run and tuned it up via the hi/lo screws, running beautiful and strimmer round the back garden. Put it away and went to do a job for a neighbour and started it up but completely out of tune again, kept dying when I squeezed the throttle. So I tuned it again, got the job done. Left a week or so and picked it up and the same thing happened again. I was just looking for some advice or pointers as to what the problem might be? Many thanks in advance, Steve

[grendel]

are there any springs on the adjuster screws, these help the screws to not move by themselves. or maybe some of the soft loctite stuff that doesnt set solid and just gives a little resistance to the screws turning themselves.

[jezza]

hi as Grendel says check the springs on the jets  also check the motoring and metering diaphragms in the carburetor they could have pin holes in them  also check the carb make wilbro and zama  jets tend to screw in to their seats then  turn out one turn tillotsons usually screw out till they stop then screw in one turn these settings can then be fine tuned once the engines running   jezza