B&S lawn mower 650 will not start without starting fluid.

[Petriw]

650 engine will not start without starting fluid. Once started it will continue to run smooth and normal. Has new spark plug and air filter.
Dirty carb? Primer not working?

 

[Scrubcadet10]

need the model number of the engine.
if its an older L head engine it will be stamped around thr spark plug area or on a flap above the muffler. Now if its a newer OHV engine, that's on a sticker... and no telling if the sticker is still on the front of the air filter or not.

 

[hlw49]

Primer on the air box if it is the air box is warped and will need to be replaced

 

[Petriw]

need the model number of the engine.
if its an older L head engine it will be stamped around thr spark plug area or on a flap above the muffler. Now if its a newer OHV engine, that's on a sticker... and no telling if the sticker is still on the front of the air filter or not.

124T02 0231 B1

 

[StarTech]

These flat prime base tend to warp leading to the primer not working. When putting a primer gasket lightly torque the screws and then remove the primer base and look at the gasket. It show areas of non contact. When I see this this I make a wedge gasket using two gaskets glue together and cut into a wedge shape to add more pressure to areas needing more contact.

Also this warpage can be cause by over tightening the retaining screws.

 

[Petriw]

Primer on the air box if it is the air box is warped and will need to be replaced

Does not appear warped. Replaced Air box to carb gasket, primer bulb. Cleaned

Primer on the air box if it is the air box is warped and will need to be replaced

Mower starts and runs on 3-5 pushes of primer bulb. Also cleaned carb, and flushed all passages

 

[slomo]

Does not appear warped.

Might not see it with your eyes.