2008 ydra (Drive) slow crank no start

[mplsfats]

We have a 2008 gas YDRA (Drive) that will not start right away at times. When you press the gas pedal the starter turns slow but will not fire. We have tried charging the batt and even replacing it. Any ideas on what could be causing this? Voltage regulator? Relay? Any help is appreciated. Thanks for looking.

[pistolpete]

i would think it would be in the big wires goin to the starter /gen. either the power wire or the ground.