I've read about ROot's mission to RUssia and I know he said "no loan no fight." I wash not aware of a specific connection to the Kerensky Offensive.
When your negotiating, I am sure your going to ask for things, so Root is going to ask for stuff and the Russians are going to ask for stuff too, with some amount of bluff going on in the negotiating tactics, if Root never arrives though the Russians will have to make their own decisions based on current conditions. No Kerensky offensive, but stay in the line seems reasonable.
I would be worried without USA loans to Britain, France that pipeline of stuff coming down the Murmansk railway starts to dry up. Western front offensives don't happen, The Germans launch a major offensive somewhere in the fall of 17 (a bigger Italian offensive, a bigger Moldovan offensive, something in Salonika, etc...)