Chain saw advice please
 

My nephew has the STHL 660 chain saw and he said it is unusually running high RPM at idle and he doesn’t know why or how to correct it. I am not an engineer but I know we have some clever people on the forum who might know the answer to his chain saw problem?

First thing to check is a sticky cable or switch Phil, the throttle may not be returning to its stop position.

Thanks Andy, I will pop round and have a look. I will let you know how it goes.

It should have a throttle stop/adjuster on it.If you can locate that then run it up to temp and see if you can adjust it to slow it down.;)

That what I did with mine.


http://www.madsens1.com/saw_carb_tune.htm

Thank you John, most helpful. I copied and pasted your experiences and your link to him in message. I haven't heard back yet.

Excuse my hijack here Phil, but I have a problem with my hedgecutter.It looses revs and cuts out after only about 10 mins of use, I have had the fuel and inlet pipe replaced, the mixture was reset by a so called 2t expert,who apparently used it for 30 mins trouble free on his own hedge. When I fetched it back from the repairets and usec it straight away,,, after 10 mins.and using it on its side,it dies. Someone said knackered carburettor? Anyone any ideas?

Hi Rich - I would strip the carb, run carb cleaner through all the orifices and then rebuild with a new diaphragm/needle/filter screen kit. I can send you links to how it is done if you fancy having a go. It's all quite straightforward if you mark everything up and take photographs of where all the bits go.

But first, make surre there is nothing blocking airflow to the fins thus causing the engine to overheat.

If it only does it when it is on its side check that the fuel pick up in the tank is not stuck up or kinked over.It should have a weight on the end of the fuel line to keep it in the fuel.

the only thing that normally goes wrong with the carb is the diaphragm that acts as a pump There is little else that can go wrong with them..:shrug:

its already had a carb strip, clean and rebuild Maninder.

Its had the tank off and cleaned, fresh petrol added, not JUST when on its side, using it on the flat too.The machone cost me 90 quid about 4 years ago, so far I have spent 50 on repairs that havent worked. To put it in to a garden machinery repair centre would cost me more than I paid for it. There is a place just across the road from me, but they are Stihl and Husquvarna dealers, so will cost a fortune. I'm not confident to dismantle it, this is why I gave it to the machinery repair man, as he serviced the mower a couple of years back. I have learnt that if I'm not sure of what I'm doing, let someone who is do the job.