if your engine is a brigs and stratten 25 thou is ok but if the engine has been standing for a long time the filter in the petrol tank will be blocked and it entails droping the tank away from the carburettor and cleaning the filter which is at the bottom of the 2 pipes that hang down from the carburettor one is about three time's as long as the other .
If the engine is a honda and you have no spark check the OIL level in the engine because the honda has a switch that kills the electric's when the oil level runs low and you can not damage the engine by runnig low on oil i hope this make's sense to you and it help's
jacob marley