2-cycle bulb primer ?'s

[jwales]

There is never a stupid question......right?
Ok a bulb primer that is not physically attached to the carburetor; has a fuel line from the tank to the primer and a line from the carburetor to the primer. The Two line fittings on the primer appear identical. with those two lines coming into the primer; if they were switched would it change the effective operation of the primer?? So does it matter which line goes on which connection?
Looking at the primer (without tearing it apart) it does not look like it should matter.

Thanks

[rogerf]

G'day,

Yes it does matter which way round the primer bulb lines go.

There's a check valve in the primer to ensure correct operation just the same as if it was on the carby.

The way to check if you've got them the correct way round is to observe the submerged fuel filter when operating the primer bulb. If it blows bubbles the lines are the wrong way round and it won't prime. There could be more 'scientific' ways of checking, but the bubble test works for me and it doesn't need anything special, just your eyes and some fuel.

Cheers from a wintery Oz☺

[KE4AVB]

Most of the ones I replace are the Walbro style. They are labeled as to which is which but most times the center is out and other is the suction side.

The suggestion by rogerf of using a couple short lines submegred in fuel mix works too as can see which way fuel is flowing.

Also when connecting the primer you want sucking fuel/air from the carburetor and not pushing fuel into it.

[Deere2me]

There is never a stupid question......right?
Ok a bulb primer that is not physically attached to the carburetor; has a fuel line from the tank to the primer and a line from the carburetor to the primer. The Two line fittings on the primer appear identical. with those two lines coming into the primer; if they were switched would it change the effective operation of the primer?? So does it matter which line goes on which connection?
Looking at the primer (without tearing it apart) it does not look like it should matter.

Thanks

Wrong!! I could direct yer attention to several posts that could be construed as ......! Yours ain't one of em, though! But I digress...

Some ( most) small snap-in type primer bulbs actually have a short and a long hose nipple. The long one ( outlet) goes to the fuel tank. The short one (inlet) comes from the metering side of the carb.
One way to check which is which, is to depress the bulb, then hold your fingertip over one of the nipples. If the bulb stays collapsed, then that nipple is the inlet side, and gets connected to the carb's metering side. ( assuming the bulb is good)
As AVB mentioned, the fuel comes from the tank feed/filter, thru the carb, to the primer, and then back to the tank. Basically yer sucking the fuel from the tank, thru the carb , thru/via the primer bulb and then back to the tank.