G'day Norm,
Sounds like a fuel issue ,
I only use BP Ultimate with mowers as I have less trouble than with other fuels.,It's a good experiment you drain out all the old fuel replace with BP Ultimate and try to start the motor.
As we know.
The degradation of fuel when exposed to heat, light, and air can occur more quickly than the general shelf life when stored under optimal conditions. While itβs difficult to provide an exact timeframe because several factors come into play, here are some general estimates regarding how quickly fuel can "go off" under these conditions:
Factors Affecting Degradation Speed
Heat: Higher temperatures can accelerate the breakdown of fuel. If gasoline is kept in a hot environment (like a vehicle parked in direct sunlight), it can start to degrade within a few weeks. In extreme heat (over 90Β°F / 32Β°C), degradation may begin within one to two weeks.
Light: Direct sunlight can also contribute to the breakdown of fuel, particularly due to heat and the photochemical reactions that can occur. Gasoline exposed to light may begin to degrade within two to three weeks.
Air: Exposure to air allows for the oxidation of fuel, which can lead to the formation of gums and varnishes. With exposure to air, fuel can start to show signs of degradation in as little as a few weeks.
Minimum Timeframe
Given these conditions, fuel can start to go off within two to four weeks when consistently exposed to heat, light, and air. More pronounced effects can typically be seen after one month of such exposure.
I'd drain the fuel /fuel bowl and make sure the fuel side is flowing properly and not gummed up ,I've heard of a plastic flap in the fuel hose spigot in the tank closing off sometimes as it wasn't deburred properly also seen new motors with debris in the tank and carby,
Cheers
Max.
