Sauerbraten with a 1.1 pound beef rump roast The recipe I'm using says to roast a 3.5-4 pound sauerbraten roast at 325F for approximately 4 hours. I'm making the recipe quite a bit smaller with a 1.1 pound roast.  

Should I change the cooking time/temperature? I'm new to roasts, so I really appreciate any insight!
Sauerbraten is meant to be cooked low and slow (schmoren), not like an American roast which has to be removed from the oven as soon as it reaches a target internal temperature. Keep both the oven temperature and the 4 hour time, do not remove it after it reaches the target temperature. 

For some background, read SAJ14SAJ's answer to How can you tell when a roast is done?. It is the section on low and slow roasting that applies to Sauerbraten.