When playing 2 player dominoes, what is the max number of doubles you can pull before you redraw?

Here is the scenario: I am playing my buddy and on the draw of 7, I grab 4 doubles. When I play on the boat, we put the dominoes back in and re-shuffle when someone draws 4 doubles. He thinks it is 5 doubles when playing with 2 players. Does anyone know the answer? Thanks|||in the league i play in there is no limit for singles