Mower Starts Then Shuts Off

[maxcalvada]

Have a 3 year old Poulan with B&S engine. When I prime it, it starts up at very fast RPM speed for a few seconds then shuts off. It seems if I pump the primer more than usual, it might fun a little longer, but then shuts off.

It's not getting any fuel once it starts up?

 

[pugaltitude]

Have a 3 year old Poulan with B&S engine. When I prime it, it starts up at very fast RPM speed for a few seconds then shuts off. It seems if I pump the primer more than usual, it might fun a little longer, but then shuts off.

It's not getting any fuel once it starts up?

Has it got a primer fitted to the carb on the metal fuel tank?
Sounds like the diaphragm has had it.

 

[SONOFADOCKER]

Did you leave has in it over the winter ?
If so take pictures of it as you take it apart .
Soak the parts in carb cleaner , brush off dirt varnish & put it back together .

 

[maxcalvada]

Has it got a primer fitted to the carb on the metal fuel tank?

Yes, there is a rubber primer pump above the metal gas tank.

Did you leave has in it over the winter ?
If so take pictures of it as you take it apart .
Soak the parts in carb cleaner , brush off dirt varnish & put it back together .

I think I drained it before winter, but this problem started last fall, I just didn't get around to taking of it till now.

Yesterday, I took the carb off and cleaned it out with carb cleaner. I've reinstalled it, but now the primer won't pump won't work - not pumping any fuel.

Confused.

 

[pugaltitude]

Yes, there is a rubber primer pump above the metal gas tank.

You will probably need to replace the diaphragm between the tank and carb.
The Briggs part no is 795083.

 

[maxcalvada]

Thanks will replace the diaphragm.

For my own education, why does a bad diaphragm make the mower not work. I read there is a vacuum created in the carb. With a bad diaphragm is there air getting in and undoing the vacuum?