Lawn Care
Lawn Mowers and Garden Tools

What would cause a Briggs and stratton 4.5 HP lawn mower from starting?

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Wiki User
August 28, 2011 8:03PM

If it will start but dies like it is running out of gas, it is

most likely the small o ring that the float needle goes into. The

new gas mixture that has been forced on that mixes alcohol in the

gas and causes that o ring to swell and effectively shuts the gas

off too early not allowing the float bowl to fill up. The cure is a

carb overhaul kit for around $8. You cannot buy the o-ring separate

and I have not found any substitutes that can handle this new

federally mandated abuse forced upon us.

After installing the new o-ring use sta-bill on the gas this

supposed to help but I wouldn't count on it too much try to run the

gas out of the carb or drain it if not being used for a long


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