I have a 1972 Cub Low Boy 154. It has the C60 flat 4 cly. engine. I used Marvel oil in it. I had 1 cly that was using oil bad. Fouled the spark with oil. The guys on the tractor forum said to try it. I did and it worked. It took 2 oil changes for it to work.
I use Lucas oil treatment in my truck. I was unable to get some once and my lifers started to tick. I put it in the next oil change and it stopped ticking. If it is just a little gunk this can work and as steveF said it cant hurt.