Why is my chiffon cake so wet?

Hi,

I use the following recipe to bake a chiffon cake, but I find that the cake is too wet and sticks together when I cut it:

These ingredients are mixed together

200g Self Raising Flour 8 egg yolks 100g caster sugar 6 tablespoons corn oil 4 tablespoons water 1 cup banana puree

These are whisked together

8 egg whites 100g caster sugar half teaspoon cream of tartar

The egg white is mixed with the flour mixture and baked at 150 deg C for about 1 hour.

Could anyone give me some advice what I should do?

Thank you