OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Four Stroke Lawn Mower Frames B&S Butterfly Carb problem

I have had this mower for a little while now and have decided to get it running to get rid of it. I finally got it to start today but it keeps sucking the butterfly shut causing it to stall. If i physically hold the butterfly open with my hand it will run quite well but once i let it go it sucks it shut again.

Any ideas?

I think you may be missing the govenor spring that goes on the arm from the butterfly to the block

it has a spring on it... but it doesn't do much

Josh84 the motor usually has two springs one for the idle speed and one for the governor. Also you could could have a bent arm that the spring connect too.

Which one am i missing the the above pic?... Its the attachment.

Cheers

Josh

or is the choke (outer butterfly the one snapping shut?

If so I found it very worthwhile on a motor the same as what you have to upgrade it to a primer bulb

no the choke one is fine. It did originally run a primer bulb but that setup was plastic and it was bent. So i used the one off the Quantum motor i had.

Josh,

The screw nearest the cylinder (in your picture) is an adjustment for the high. Try undoing it a bit while you have the motor on full throttle and see what happens.

Hi all,
I too, have had allot of trouble with the carbys off quantum�s, they seem to be ill designed.
Seeing as the carby is not original it may have problems with back pressure sucking the vane closed (I have had problems with transplants of priming in place of chok-a-matic).
regards jay