Timing is not something the average joe can do, even if you can clean and lube. It takes a special tool to set the needle height, this has to be precise for the needle to catch the bobbin thread correctly. You may want to have it cleaned and adjusted for preventive maintenance, and have them check the gears and belts. I was a HandiQuilter dealer for 4 years and I can't emphasize the importance of scheduled maintenance.
OzarksGma