Small Engines (Lawn Mowers, etc.)/Fuel leak from pump



I have a Briggs & Stratton 11.5hp engine (model: 21A977-0122-E1) on a ride-on (Stockman series 2) mower and have fuel leaking after a few minutes of use. It leaks from a gold mesh type hole on the fuel pump. I have replaced the fuel pump, as well as the fuel filter and fuel line to the tank. All to no effect.

It started when I filled the tank and noticed a leak on the fuel line from the fuel filter to the pump. That line was old and cracked, so I replaced it, but it now seems to leak from the fuel pump (even after replacing the pump!).

I am a complete novice at this, but was hoping to avoid taking it in to a technician...

Any suggestions would be greatly appreciated!


Hi Andrew

is your fuel tank mounted quite high ?  and your fuel pump mounted  low  
it may have too much head pressure  and head pressure is overcomming  diaphram  and leaking out comming out the vent.

was this engine a repower from the original unit that mower came with ?

as with any mass produced item it is still possible that you have a faulty fuel pump?
especially if your tank is mounted low  and your fuel pump is mounted on side of engine as it normally would at rear l/h side with most briggs  engines , but to be sure have the shop where you brought it test it for you in accordance with briggs test proceedure  using a hand pressure tester

are you sure you have vaccum pipe to the vaccuum side  marked  VAC ( this comes accross  from oil filler tube )and the outlet hose connected to the outlet triangle marking pointing OUT    and the inlet hose to the inlet nipple  marked with the triangle pointing IN

other than that thats all i can think of

cheers  hope it helps

here is web site  for parts
downlaod  exploded parts diagram as below
select iluustrated parts list

cheers  paul  

Small Engines (Lawn Mowers, etc.)

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Briggs and Stratton MST qualified Tech - Certified Kohler Expert Tech 12 years experience in repair of Small Engines -Briggs,singles, twins Kohler, Honda , Kawasaki ----Husqvarna chainsaws and trimmers -shindiawa -chainsaws & trimmers etc Walker Mowers - Kubota Ride ons - Husqvarna ride on and outdoor power equipment, -Mtd Ride Ons, Push mowers etc


Briggs and stratton MST qualified Tech - Certified Kohler Expert tech 12 years experience in repair of small engines Husqvarna chainsaws and trimmers -shindiawa -chainsaws & trimmers etc WALKER zero turn mowers Kubota Ride on mowers Husqvarna ride on and outdoor power equipment Mtd Ride Ons, Push mowers etc some experience in 2 and 4 wheeler repair - Honda, Suzuki , Yamaha

Qualification - Briggs and stratton Master Service Tech 2005 onwards Qualification - Kohler Certified Tech Qualification - Mito NZQA National Certificate Outdoor Power Equipment Basic automotive trade skills & year 2 & 3 of Motorcycle engineering

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