I've had the BG85 about three months now. Not to much use on it. Well after it warms up for the day, it becomes extremely hard to start, and will only idle. When I try to rev the throttle it dies. Gas is good, mixed properly. I have replaced the spark plug and air filter. No change. It will not run properly again until letting it cool down for several hours. Which does not exactly lend itself to use on a tight route. Once I get it running it seems fine. I am at wits end. Any suggestion? Thanks!