" GA Instable

Hello,


I'm using a simple genetic algorithm to solve a maximization problem and I
encounter the following problem:

Contiguous runnings of the algoritm "may" be resulted to different solutions
with big distances between them!!!
My algorithm uses the basic getic operators:

                        sus selection
                        one point crossover
                        mutation
                        reinsertion without elitism

In other words there is instability about the performance of the algorithm.

Why this event is happened and due to ??



Thanks
George