How would I adjust the choke on my Briggs & Stratton 675 Series? where could I find the repair manual to download free online

The manual refers to an 'engine manual'.

https://images.homedepot-static.com/catalog/pdfimages/9c/9c9737f9-bd0c-46ea-a819-68346072e3e1.pdf

These are more helpful, although you have to refer to the engine model and not the lawnmower model.

Briggs and Stratton Valve Clearances

https://outdoorpowerinfo.com > briggs_valve_gaps

Intake and Exhaust Clearances for Briggs & Stratton engines used on a variety of outdoor power ... Model Series, Engine Type, Intake Valve Clearance ( in. ) ...
Missing: 126t02 ‎' Must include: 126t02

Engine Valve Repair Maintenance ' Briggs & Stratton

https://www.briggsandstratton.com > faqs > browse > va...

WARNING: Always read the engine and equipment manual(s) before starting, operating, or servicing your ... Adjusting Tappet Clearances & Overhead Valves.

there are holes in it should be three or four. a rubber diaphram is covering it but they are there

https://www.jackssmallengines.com/jacks-parts-lookup/manufacturer/briggs-stratton/100000-19z999-series/15t200-to-15t299/15t212-0223-f8/blower-housing-electric-starter-flywheel-rewind-starter

Manuals - Briggs & Stratton

https://www.briggsandstratton.com/us/en/.../manuals
Briggs & StrattonFind Briggs & Stratton manuals online by selecting your lawn mower or product type &engine model number. Never worry about losing an owners manual ...

clean the carburetor clean the fuel line filter adjust the idle screw on the carb as well

Check the compression of the motor

Remove the air cleaner cover and the air filter then spray into the filter box.

It may not have one. Some mowers auto choke using spring tension on the choke plate in the carb. They open the choke when the engine speeds up after starting.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/david_29ad5d1dd86564b0

Many Briggs engine have a primer rather than a choke, the 675 series has a choke that is worked by an air vain, the choke is always closed when the engine is stopped, once the engine starts air pressure from the flywheel pushes the air vain which in turn opens the choke to allow the engine to run normally, there is also a version with a bi thermal switch on the back of the muffler, as the muffler heats up the switch opens the choke.

This may be of some help to you.

http://engines.myfaqcenter.com/Answer.aspx?p_faqid=3353&selectCats=Troubleshooting - Repairs