It would not be possible for you to do this without doing it illegally.
In order to work in Turkey you need to get a work permit and to get a work permit you need to be doing a job that a turkish person could not do. Generally the main kinds of work for british people are holiday reps, estate agency and teaching sectors. There are other jobs but they tend to be more skilled.
Also I have not really seen many lifeguards in
Icmeler and Marmaris. I used to work as a rep and I can't name one
hotel that had a lifeguard even the 5* ones. I tell a lie, I actually think they may have had one at the Mares but they weren't always there and when they were they were asleep on the big chair thing!
I didnt ever see any on the beach either although I was always working and never got to spend much time on the beach, maybe they do have them and I just haven't seen them.
It would be very hard to work as a lifeguard in Turkey too, unless you have a good knowledge of turkish. How would you know what people were telling you to do or how to call for an ambulance and liaise with paramedics etc? Maybe you have a good grasp on the language so if you do I apologise.
Working in Turkey is very different to holidaying there and is really really hard work. Its impossible to work in that heat with a hangover (people do it but you can't work properly only muddle through the day!), you don't get much time off and the money is terrible. On the same hand I had the time of my life when I worked there, met some of my now best friends and really do miss it! Read the other posts on working in turkey but I thikn the lifeguard thing just wouldn't be possible.
Lea x