I will try to describe the problem as best as I can since I don't know the English technical terms. Here is what my RX8 does:

I tried to start my car yesterday. When I turn the ignition switch to start, instead of making that 3-4 engine cycles and then starting the engine, my car makes a continues single cycle and the engine never starts. When I release the key, I hear the engine slowly decreasing its noise (like electrical equipment noise). I have tried several times, even today but it's the same. The noise is so strange that I think maybe I damage something.

If I described correctly, is this a starter issue? (could it be the whle starter or just a consumable part of the starter)?
Is this something that I could repair myself easily if I purchase the proper parts or it necessarily needs an electrician? (the car is in my parking and nobody will come here to start it)

 

We need to know exactly whats turning to properly diagnosis this.

If the engine is turning over while starting, the car could be flooded.
Search the many threads on this topic.

You also mentioned when you release the key, the "electric equipment" sound slows down.
So if the engine is not turning over when you attempt to start, two things come to mind:
1) Bad starter.
Remove the two bolts for the starter and pull it out.

Have someone start the car while you watch the starter.

Referring to the pic above, you should see the drive gear move towards the front and start spinning.
If it doesn't perform one of those actions, the starter is bad.

2) Flywheel's gear ring came loose (unlikely, but I've seen it happen).
With the starter removed, reach in the opening (where the starter is inserted) and attempt to spin the ring gear.
If you can spin it, the ring gear came off the flywheel and you have more work ahead of you.
Here are a couple pics, the left pic shows the flywheel without the ring gear and the right pic shows just the ring next to my used flywheel.

 

try charging your battery ... my optima died... it was at 10 percent last night!!!!!

 

^If the interior lights dim as you attempt to start, then yes... charge the battery.

Another thought...
The "electrical equipment noise" andreasy mentioned hearing decreasing in sound may just be the air pump.
Might have to do some Process Of Elimination.

 

Watch the pulley as the engine is cranked. If the pulley is turning, then the starter is turning the engine. In this case, most likely your engine is flooded.

If the pulley doesn't move, then the starter motor is not engaging the flywheel.

 

It was not the starter after all. An electrician examined it and he had to take it at the garage as he couldn't find what the problem is.

The pulley is turning and the statrer works as well.

 

Appears to be flooded then. Unless of course you have the old starter ('04 and early '05) and it's not turning over fast enough to start the engine.

 

Is there any way to tell if you have the old starter? I have an '05.

 

Here's the TSB

 

Really need more car info...what year?, mileage??...

Where do you live??

If you are North of the Equator and in Winter then I suggest it could just be your battery..

ANY Battery over 3-4 years old can have issues....

 

Thanks, I got my car back finally from the garage. Unfortunately no one was there to explain what was the problem but I believe it was flooded as they didn't change any parts. The real question though, is why would it get flooded. I haven't recently done anything strange (I started the car just to take it out of the garage a few days ago and switched off when I was out but I used the car a few more times after that. If it was due to switch on and off within a short period of time, wouldn't it get flooded right at that time?). After this, I drove the car quite normally and then it happened.