The amount depends on how well you got the old out when draining. I found it drains out more with the front end in the air. That being said, 1.9 qts always seems to be too much. 1.3 -1.5 is about right. The important thing is, you want the oil at the bottom of the sight gauge cold( run the engine for a minute, and then shut it off for a minute and check). when the engine is hot, the level should climb to about 3/4 sight. It is important not to overfill this engine, it will cause overheating, and power loss. There is an entire 6 pages devoted to oil changes, and a HOW TO section on predatorowners.com.