UKC

I have A Ryobi chainsaw been starting fine for 2 years cutting no problem

Last 2 times I started it work it for 10 mins then its stops, and will not start when warm leave it to go cold it starts fine again?

I Checked spark when cold it is fine but when it is warm no spark at all put brand new plug in today and still the same so not spark plug

Any clue to what I should check for next?

thanks for the help in advance

In reply to Johnf:

How old is the fuel? Any crap on the pickup filter in the tank?

In reply to Johnf:

I'd bet good money on it being a problem with the coil.

In reply to Johnf:

No coil on these, just a magneto. These tend to be fairly reliable, so the issue is probably with the earthing system between the magneto and the plug. There is usually a grounding switch to stop the engine, that would be my first port of call.
Oh, and fuel, however bad, won't cause spark problems.

In reply to Johnf:

Try cleaning/changing the air filter.

In reply to bearman68:

I need to learn to read apparently...