The 574 Prefix Sears Engines were made by McCulloch. In addition to Laings you can try discount marine parts in Wisconsin. All you may need is a good basic tune-up….clean and adjust the points, clean or replace the plugs, take the carb off and give it a thorough cleaning. You may need a bowl gasket to do that or you may well be able to re-use the one on there.
http://discount-marine-parts.com/ob_elgin_mcculloch_model.html
That’s a good motor; I wish it were mine LOL!