Look for a mark on the block (not the pulley) that the "F1, F2 or F3" would line up with. I would think the mark on the block would be on a machined area, rather then the casting surface. After all those years of operation, the machined surface might be a bit rusty...so look or feel for a relatively smooth surface.
Those marks probably indicate Top Dead Center (TDC) and a given number of degrees before and after TDC (for example, F1 could be TDC, F2 could be 10° before TDC...). Or, F1, F2 and F3 might be TDC for each individual cylinder, if your Kioti is a three cylinder engine. I should hope your manual defines what the F1, F2 and F3 markings are used for. If your machine is a three cylinder, do not assume they're numbering the cylinders from front to back!
The only time I've seen timing marks used without a timing light was for adjustment purposes, not checking the time. However, that was on gas engines, not diesels.
Here's a little
info on timing diesels.
Just make sure you know what you're doing before you attempt this task!