Issues starting engine (Seat Ibiza 98 1.0i)

[acce]

Hi. I recently found this great forum. I've an issue I hope that you can help me with.

Car: SEAT Ibiza mk2 1998 1.0i (50hp).
Engine code: AER

Issue: The car has been standing still for two months. Now it has issues starting.The battery was completely drained but is now fully charged and the engine sounds fine when the key is turned.
However, it takes about 20-30 seconds with the key turned and gas pedel fully engaged/pumped before the car actually starts. See attached youtube video. When the car is started it is idling fine and the engine sounds great. However, at "hard" accelerations the engine is stuttering/lagging. Otherwise, it's running great.

Checked: Based on information on this forum I've already done the following:
- Cleaned the throttle house with carburetor cleaner
- Checked the rotor arm and distribution cap
- Checked the spark plugs.

It sounds like the car doesn't get the right mixture of air/gasolin? Does anybody have any idea what I can try now?

YouTube video:

 

[Legojon]

If it wasn't for "However, at "hard" accelerations the engine is stuttering/lagging. Otherwise, it's running great.". I'd have said weak starter motor.

 

[bete noir]

Was it running OK before it was laid-up? Did you put fresh fuel in it?

 

[acce]

Was it running OK before it was laid-up? Did you put fresh fuel in it?

Yes it was running OK before the laid-up. The tank was almost empty so I filled it about 50%

 

[acce]

Solution: it seemed that the gas in the tank was polluted somehow. I added some fuel system cleaner to the tank and filled it up. After a couple of tanks with cleaner, the car is now starting perfectly again.