Welcome aboard fido_44, you probably have realized all the answers you need on your own, but
Over the years I've dealt with many types of customers. Some need motivating, some will never be motivated. Allowing 4 months to pass without a call asking "so how's it going?" is an error you should also never make.
As a provider, it allows it to fade into memory: every time you re-visit the project, you have to almost learn it over because so many other projects have crossed your desk in that time. The same is true of the client, except that as a "buyer" of services, their view is likely, "we have someone doing that, haven't heard from them in 4 months." I hear this all.the.time when cold calling potential clients, and the disdain is obvious.
Falling out of constant communication with the client is the one sure way to kill a project, IMO. It's no fun "doing someone's job for them" but sometimes that's what it takes to keep them in the game.
Short term projects, I make contact every day - how I'm doing, or if I'm waiting on something, how they are doing. On longer term projects, at **least** once a week. People seldom move unless you make them move, and this gives the impression you're a "go-getter."
If a client doesn't respond to this, I let them know the project is floundering, and offer help (as you did.) If repeated contacts and offers to assist don't make anything happen, I let them know: I have to schedule time for new clients, we have to wrap this up ( = "last call, can I help you or not?")
If nothing happens, I let them know, this project is closed, contact me when you are ready. Then we move on.
But 4 months? I'd expect them to forget my name! :-)