Is there a flying club in your area? It would be good to take it to someone that knows what they are doing and have them see if there is a problem. Hard to tell you what to do with the info given. If there is a problem, you could be screwing it up running it. It may be normal though. Hard to tell from the description.

I would find someone close to you and have them help you check it out. Even if you have to drive an hour or two, it is cheaper than fixing a screwed up engine.