How to remove casing on jet pump?

[Garnet]

I have a 1/2 hp shallow well jet pump. The brand is Home Plumber professional series from home hardware.

I want to replace impeller. Instructions said to remove 4 bolts and the casing. Does not say how to remove casing.

I have been pulling and prying but doesn't budge. With the 4 bolts removed i can spin casing. Just wont separate. Any suggestions?

 

[Garnet]

K. Figured it out. There was a gasket that was covered with rust. Was able to get a flat head in there and pry it apart.