Stihl 031 Problem

[Alan F]

I have a Stihl 031AV that has given me excellent reliable service for many years.  Recently it has developed a problem - it starts easliy, runs normally for about five minutes, and then suddenly stops. It will not start again for some time, presumably until it has cooled down.

Do you have any suggestions as to what could be causing this problem, and how I can fix it. Someone suggested that it needed a new carby kit. I had that put in, but the problem remains. (It is the model with points, not electronic ignition).

The Stihl dealer tells me I need a new saw, but I don't like to part with the 031 as it is in good order (apart from this problem) and has not had a lot of use over the years. I don't think I can really justify the cost of a new saw from considering the amount of work I have for a chain saw. Also, the new saws look like they have a lot more plastic than this old one.

Thanks for your thoughts and advice.

[Kevin]

I'd be checking the plug to see if it's getting fuel when it won't start and if it's wet then I'd be checking for spark at the plug.
This should get you started in the right direction.

[joe_indi]

A possible culprit in any CB point ignition would be the capacitor.A failing capacitor could heat up rapidly, weakening out the spark, till you reach a 'no spark' situation.A short period of cooling down will make it work again.
The same holds true also for the ignition coil

joe

[wudhed]

The ignition coil wold have been my first guess also!