My lawn mower recently quit working midway through cutting my grass and wouldn't start again. I looked up the troubleshooting guides on the internet and ended up determining it was a bad spark plug. The only problem is the plug that was installed, Champion RJ19LM, was not available at my local store so I ended up buying the Champion J19LM. The lawn mower works like a champ (at least for the 15-20 seconds I let it run after it started) with the J19LM installed. My question is it safe to leave the J19LM installed or should I spend the money to have the RJ19LM shipped to me from an internet company? I would do this anyway, but shipping at the few sites I looked at doubled or tripled the cost of the spark plug (less than $2.00 locally for the J19LM). If it matters the lawn mower is a Toro Recycler model 20041. Thanks for any opinions/suggestions.