I would try a lawnmower or small engine repair shop. Some of those places will work with you and find one that will work. Some on the other hand are pretty clueless and unless you know the make and model of the engine won't talk to you. Obviously you want to find one that will work with you. Back in the day I wanted to get a plug so I went to one of these places. They had 100 plugs on the wall so I asked for a NGK B6HS and they couldn't help me unless I told them what make, model and year of the engine. Needless to say I didn't go back to that place.