If you came here for actual advice, well, first of all, I fell sorry for you but this is what worked for me so far: In an old diesel (indirect fuel injection only) I was using 5 liters of stale petrol per 70-liter tank. Żuk is an old petrol, with a very low compression ratio and it will go even on 70 (RON) octane fuel and I am using 95, so here even 5 liters per 40-liter tank work ok and there is 0 difference in power, only smokes more when this fuel is already mixed with 2-stroke oil. This doesn't mean that it will work for you, better always start with lower doses ;) and remember, stay cheap and do stupid stuff, otherwise there will be nothing to fix!