Keras deep learning why validation accuracy stuck in a value every time?
It could mean that the model has learned everything possible and can't improve further.
One of the possible ways to improve accuracy is to get new data. You have ~4 samples per class, which is rather low. Try to get more samples or use data augmentation technics.
I am trying to train InceptionV3 network with my custom dataset (36 classes 130 samples per each). And some parameters fro my network: