They are good engines mines 6 years old and still going. Yes you can get parts for them. make sure your back plate is tight if it has a leak that could explain the doggy performance as you put it.

It sounds like your new to this I can't recommend enough how much easier and quicker you'll learn to handle these engines if you skip the internet forums and get in person help from an experienced modeler. You'll pick up the basics in nothing flat.