The most common extinguisher here is the 5lb CO2 - basically the same as the 2kg one you are talking about.

Halon is another option, and I have one of them - but getting Halon refilled can be harder then getting CO2 refilled.

The water extinguisher may be used for e.g. putting out any grass fires that you start, but I wouldn't use it on the turbine. Dry powder should also not be used on the actual turbine unless you have absolutely no other option at the time and need to put the fire out regardless of the damage that you are about to inflict on the engine with that extinguisher. (The powder will act as an abrasive - you may as well put the engine in a sand-blasting machine.)

Gordon