This is a compact riding mower given to me by a friend with a small trade. I need to work on the engine because it is doing blow by with heavy carbon and moisture of oil on the spark plug.

My problem is the hydro-static gear box. There is a lever to manipulate whenever you need to manually push the mower, otherwise it has a control position when using the engine to mobilize. I am having trouble getting the gear box into neutral. If I rotate one wheel say clockwise the opposite wheel rotates counter clockwise.
I went to to see if a manual could be obtained or a schematic for the model which I identify correctly but then it goes into a loop. Model 7-1197.
Anyone out there know about this hydrostatic gear box or where I can get necessary information?

Thank You