i need a air cleaner cover,2oil plugs and ignition switch for a greyhound 11 hp engine

I did not come across the exact part matches but did find a few retailers that may have the parts you need. I recommend Harbor Freight as your first location. The contact information is as follows-

BY PHONE: Call 1-800-444-3353, Monday thru Friday,
6:00 am to 4:30 pm PST time, to speak with a friendly
Customer Service representative who can help you with
any order questions.

To place an order by phone, please call 1-800-423-2567,
24 Hours A Day / 7 Days A Week.

For technical product questions, please call 1-888-866-5797,
Monday thru Friday, 6:00 am to 6:00 pm PST.

BY FAX: Fax your concern to 1-800-905-5215 or 1-805-445-4912.


BY MAIL: Write to: Harbor Freight Customer Service,
3491 Mission Oaks Blvd., Camarillo, CA  93011-5034.

BY EMAIL: Please click on one of the subjects below.
Note: Emails are usually answered within 24-48 hours.

I added other options as well below. Just click on the links and you are on your way!