TVO vs PETROL

To answer your question, no it won't harm the engine to run it on petrol alone.

Of more interest is that you say your engine is sooting up, which may indicate a rich mixture anyway, so running it on petrol may not help fix the problem.

If you don't want to buy your TVo in 44 gallon drums, try this mix:-

4 gallons paraffin
1 gallon petrol
250ml two-stroke oil (for the smell and upper cylinder lubrication)
1 pint of diesel (optional - mine doesn't like it)

There are other variations, but they are all about the same.

I think I'm right in saying that TVO has a slightly higher calorific value than petrol, so you can usually throttle back a bit when running on TVO - this helps economy a lot.

James, UK

Whether it will cause damage if the mixture is adjusted properly I really don't know.

There are TVO mix recipes about that would let you mix a TVO substitute that would probably be more economical than petrol and avoid any risk of damage. But I realise that maybe you're asking the question for an entirely different reason.