Looking for the main serial number on a Stihl 021 saw

Hello, Stack -

I found the following information by going to the Stihl home page:
https://www.stihlusa.com/

On that page, I chose the link to FAQs (Frequently Asked Questions) and came to this page:
https://www.stihlusa.com/faq/

I chose the button named "Get Into Now" which brought me to this page:
https://www.stihlusa.com/faq/products/

I chose the link for Blowers. This is the link to that page:
https://www.stihlusa.com/faq/products/blowers-sprayers/

This is the 6th question on that page:
(Quote)
Where do I find my serial number?
(I chose that question and saw this answer.)
On handheld blowers and shredder vacs, it is located on the bar code label on the fan casing. On backpack blowers, it is on the bar code label and stamped in the top of the cylinder or main crank case. All current serial numbers will be nine digits long and begin with the number 2, 3, 5 or 9.
(End quote)

Best wishes.

On backpack blowers, it is on the bar code label and stamped in the top of the cylinder or main crank case. All current serial numbers will be nine digits long and begin with the number 2, 3, 5 or 9.

Source: Frequently Asked Questions about STIHL Blowers STIHL USA

Machine number? Do you mean model number? The serial number is stamped under the saw in the front.

The serial number is stamped on a plate on the left side of the main frame (or, on some models, on the right side). It is also stamped on the top center of the transmission housing.

Climb up into the tractor's seat. Look below the lower left-hand side and lower right-hand side of the steering wheel panel for the serial number. Certain older Ferguson tractors have the serial number stamped to a plate that is mounted to one of these areas of the steering wheel panel.

Serial Number Plate:

http://old20tractorparts.com/mf-165-tinwork-parts/1356-massey-ferguson-165-serial-number-plate.html

Inspect the left- and right-hand sides of the tractor's main frame. Certain older Ferguson tractors have the serial number stamped to a plate on the outside of one of these areas of the main frame.

Inspect the top of the transmission housing for the serial number. Certain older Ferguson tractors have the serial number stamped to a plate that is mounted to the top of the transmission housing.

There are six different chains with different pitches that can be used on this saw. 1/4, 3/8 PMN, and 3/8 P use a 5/32" file; 0.325 uses a 3/16" file; 3/8 uses a 13/64" file; and 0.404 chain uses a 7/32 file. The pitch is ususally stamped on the side of the chain teeth.

Hi, you cant go wrong their both stihls. The 021 is a more powerful saw and the 017 is lighter, so it all depends on your intended use. Regards Phil.

It probably goes to the ground on the choke lever. Remove the air filter and look at the area where the shut off switch is located, you should see a small slot where the wire slides in and connects with a metal piece in the stop position.

Look on the main engine frame on front under muffler. Mine is stamped on the frame right there. Hope this helps you. Thanks

Lay machine back (away from you) outside the box. On the underneath of the machine itself is a metal plate facing you with the number. The plate will be in the center and is easy to read.