honda mower drive cable trouble

[jbird3898]

My honda hrx217 kvka with the smart drive system (the one with the thumb controls) is having trouble getting full power to the wheels. i replaced the cable and still having touble. i adjusted it and it will run fine on pavement but once you get to grass it just doesnt want to go. Anyone have any tips or website that has a service manual that you can view online without paying for it.
Thanks

[mowerknower]

Pretty simple set up. Can you see if the axle keeps turning when the wheels stop. Could just have sticking keys in the wheel ratchets.