I installed a new shower unit and can only get luke warm water now. Is there an adjustment that will allow me to get the water hotter?

Need more information. What brand and model is the shower valve?

Hi, JonKukula,
If it is single handle faucet than there is a anti-scald ring behind the handle. It is factory preset at low temperature. Do this: remove handle, locate the ring, toss the ring, reinstall handle - and now you get all the hot water that is available.