Are you sure all three bolts on the front, two that are under the IP to the engine and the one on the bottom back of the IP are good and tight?
Generally rough idle is because the pump is moving too much at idle. The lever is against the stop on the top of the pump right? You might try turning in the fuel screw at the top left of the back of the pump. Release the locknut and give it a 1/4 turn in the clockwise direction. This will put more fuel into the engine at all times so just do it in a small turn at a time. The Engine speed should bump up a bit at idle doing what you just did. And it may now be necessary to release the locknut and reposition the idle stop some.
See if that helps or not.
Generally rough idle is because the pump is moving too much at idle. The lever is against the stop on the top of the pump right? You might try turning in the fuel screw at the top left of the back of the pump. Release the locknut and give it a 1/4 turn in the clockwise direction. This will put more fuel into the engine at all times so just do it in a small turn at a time. The Engine speed should bump up a bit at idle doing what you just did. And it may now be necessary to release the locknut and reposition the idle stop some.
See if that helps or not.