Our club is custodian for a 6hp magneto start Austral which is in very good mechanical condition and starts easily, but will run down and stop after some time. The time can vary from a few minutes to over an hour.
The magneto gives a strong spark and the fuel (petrol) supply is continuous. We have tried numerous spark plugs of different heat ranges and brands, but the problem persists.
I have thought that possibly when the engine warms up, the vaporizer may be creating a vapor lock situation, but the variation in time seems to contradict this. The run down can occur when both hot and cold as evidenced by the time variance, and at this stage we have not tried kerosene.
My question is:
Do other magneto start Austral owners have this problem when running on petrol, and if so, how do they fix it?