errrr you will go far wrong with that advice.
Oil dilution ratio is dependent on the quality of the 2 stroke oil you are intending to dilute with your petrol.
The manufacturer of the machine may give thier recommended ratio in the handbook, but if you look closely this is dependent on using thier own recommended oil. Rarely is it the case that a retailer can supply you will the same manufacturers oil, so you should always consult the dilution ratio which will be clearly marked on the bottle of 2 stroke oil you are using.
Varying qualities of modern oils require more or less to be added to petrol. Too much and you will over oil your engine- too little and the engine receives little or no lubrication and can be irreprably damaged.
As a good guide. Use the best quality oil you can find and afford.
The cheapest oil is Mineral oil 2-stroke which should be diluted at a ratio of 25:1
The middle ground (and the most popular today) is semi-synthetic 2-stroke oil which should be diluted at 50:1
The top quality oil is fully synthetic 2-stroke and has a dilution ratio of 100:1
As you can see- if you don't know what oil you have the effects could be disasterous if the wrong ratio is applied to the wrong oil.
Ignore completely 2-stroke brands of oil that give vague or no dilution ratio on the bottle- these are generally found in high street stores and diy stores. Go to a specialist garden machinery supplier who will have the best choice and the best quality oil
pleasant, January 2010