Thanks everyone,

I sent an email to OS and they replied already and are shipping me the part. Here is the email.

Dear Sir-

Thank you for your recent e-mail. We are always happy to hear from
fellow Modelers.

We are sorry to hear you are missing a part on your O.S. engine.

We will be glad to send you the part(s) you have requested at no charge
as a customer courtesy.

Please allow 5-7 business days for delivery.

I hope you find this information helpful. Should you have any further
questions or concerns, please do not hesitate to contact us at this
email address. (Please be sure to copy all previous emails into any
future questions.) You can also reach our product support technical
team at 217-398-8970, or via fax at 217-398-7721.

DID YOU KNOW that our web pages now all contain FAQs? (Frequently asked
questions) Please drop by and take a look! We hope you'll find the
information helpful and valuable to you.

Sincerely,
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Hobby Services