Nomad,
The 1000km figure claimed by Iran is not a combat radius, it's the RANGE. That means if the Karrar was fitted with normal set of equipment (guidance & control systems plus internal fuel) it could fly 1000km in a one-way flight.
Therefore, it you added a warhead the size of the Noor's (the minimum needed to damage a large vessel though far too small to even cripple an aircraft carrier), that would increase the Karrar's weight significantly. Lets say the Karrar has an empty weight of say 600kg (based on similar classes of drones). If you add 165kg in warhead alone you are increasing the drones weight by more than 25% and will likely take up space original used for fuel storage. This will significantly decrease the drones range. Fitted with any smaller warhead and there would be no point to it.
Also, with or without any external payload (whether it be bombs or missiles), a Karrar is almost guaranteed to be detected LONG before it will ever get within striking range of a carrier. The Karrar isn't stealthy to begin with, and any external payload would only increase the problem. Because the Karrar is so bulky (with a very exposed engine, taile design, and fixed wings), even if it was modified to act like a "sea-skimmer" and then pop-up and explode above the carrier, it's shaping makes it pretty likely to be detected long before it can damage a carrier.
Catsoo,
I agree, the Karrar's wings are much too small to carry even 4 relatively small Kosar missiles. If they redesigned the wings (making them straighter and longer) and used a more powerful engine (perhaps a small turbofan like the R95-300 used in the Kh-55 Iran imported), you could end up with something that could carry such a load.
Actually I have been working on a concept of a possible development of the Karrar that would look rather similar to the Chinese WJ600 UAV/UCAV..But that's for another day.