The easiest way is to use a standard business card between the coil and the magnet part of the flywheel.
If you mean Briggs and Stratton model 193702, then you want Briggs Stratton Carburetor Part No. 491590 It costs less than $150 USD. Check out http://www.smallenginesuppliers.com or the Briggs and Stratton website.
that is not a good model number for briggs. also you need the type.
If the first two digits of the engine's model number are the same, the answer is yes.
NO
what is the champion cross reference for a briggs and stratton spark plug 691043
You can get that info on the Briggs and Stratton website. Just go to: http://www.ereplacementparts.com/briggs-and-stratton-parts-c-16758.html?gclid=CPCZj4vGr58CFZdM5Qodp3bDsA and enter your engine model number.
It is a 2-cycle 4HP Briggs motor.
The most popular place I know of for instruction is the YouTube site at the link below.
20 oz.
Try smallenginewarehouse.com
Briggs & Stratton
Get the model # and click the link I will post.