Strimmer Keeps Cutting Out

For the cost of a spark plug I'd replace that before doing anything else.

Wasted loads of time in the past with identical issues and often putting in a new plug was the solution - but not always :-)

I've a very cheap no name chinese carb on one of my strimmers and one of my chainsaws. The strimmer one is great but not so sure about the copy on a sthil chainsaw.

From new the strimmer was always a pain to start, poor idle, poor power pick up, easily stalled etc. No end of fettling sorted it and I had it down to its component bits. A £8.99 carb from Amazon fixed all those problems.

Well, @Schorpio, did you figure out what the problem was?

Does the carb have a connection to the crank case? Often a hidden pipe at the bottom of the carb. It uses the pressure of the crankcase to pump fuel. Not all carbs work that way more common on chainsaw than strimmer.

The hole is an alternative to the pipe. I needs to be clear as it runs the little diaphragm pump in the carb. I mentioned it as if there is a pipe it sometimes gets missed. I know I've forgotten to reattach it in the past.

after more than 60 years working with small petrol engines I can give you a few tips. Firstly check your new Chinese carb and look for one or two small adjuster screws on the main body. If you see these adjustable screws that used to have a plain slot for adjustment and now require a special tool ( to comply with emissions and deter owners from fiddling) these would need to be screwed home , carefully, and then unscrewed by three half turns as a starting point. Then turned slightly clockwise to reduce fuel and anti clockwise to increase it. If you have two screws the one nearest the cylinder is a slow jet adjustment, affecting fuel supply up to half throttle, the one farthest from the cylinder is the main jet and controls full speed supply. If you don’t have a set of special tools and can manage to take the screws out you could cut a slot with a junior hacksaw for a small screwdriver. But don’t mix them up. getting them out will be difficult as there are many different versions of the screw type. after all this,the addition of ethanol E10 to petrol is causing major problems to carbs and the plastic and rubber components of the fuel systems, especially in tools that lie idle for weeks or months at a time. partially or completely blocking the internal fuel galleries in the carbs.

I used to have to replace maybe three or four carbs a year, now it can be up to thirty or more. After market carbs can be less than proper original makers ones and although cheap are not always successful.