Trying to help a elderly neighbor. She has a 2014 Troybilt Pony lawn tractor with a 15.5 briggs engine. They were running it the other day and it was running rough. Shut it off and now it will not start. Has spark, fuel and air. All safety switches work because we have spark. Now the spark is yellow at my tester and at the plug when grounded. Cleaned and dried plug it was wet and crusty. Engine turn over fast and steady. Can't put fuel in plug due to the way it is made. I do not have spray so that is out. She is going to get a new plug today and I will put that in and see what that will do. What am I missing. Thanks in advance,
Roger
Roger