Tecumseh carb question

[billb]

I have an Ariens string trimmer with a Tecumseh LEV120 motor and a 640262A carb (I think that’s what it is). It has a few hours of run time on it and has been sitting in a shed for several years.
The carb was gummed up due to neglect on my part. I took the carb apart and cleaned up everything I could and made sure all the passages were open. A new spark plug was installed and fresh gas was added.
My problem is it won’t start without a shot of starter fluid. Once I get it running, it seems ok. I don’t think the primer bulb is working.
I admit I don’t quite understand how the primer circuit works. I am assuming pressing and releasing the bulb is supposed to pull fuel out of the bowel and shoot it out of the tube towards the air cleaner. I’ve traced the circuit from the bowel pick up, up to the bulb and out to the discharge tube. Everything appears clear. I removed the primer bulb and the Welch plugs looking for blocked passages.
Can someone explain to me how this system works? I would have expected to see a check ball somewhere.
The parts diagram doesn’t show what I’m looking for. I think if I understand how this is supposed to work maybe I can get it working again.
Thanks for any advice,
Bill

 

[reynoldston]

You can replace the carburetor for around 15 dollars, replace it.

 

[BlazNT]

As I was told once "It is not primer bulb it is an air purge bulb". It is designed to remove the air from the fuel line to the carb.

 

[Rivets]

Sounds like the carb needs to be cleaned and rebuilt properly. Float level is not set properly. Kit need is 631021B, follow this procedure.

Needle and seat replacement.

Remove the carb, and then remove the float bowl. Check the float bowl jet (which is the bowl screw) and make sure the jets both horizontal and vertical are clean and open. Tip the carb upside down and remove the float pin and float with needle attached. Look in the float needle passage and you should see the red float seat at the bottom of the passage. This is where a #5 crotchet hook would come in handy as you need to remove this seat. If you have no hook, but compressed air, you can blow through the fuel inlet and try to pop the seat out. Put your thumb over the passage to prevent the seat from flying who knows where. No air or hook try bending a stiff paper clip to dig the seat out.

I would either give the carb a good 24 hour soaking or have it ultrasonically cleaned at this time.

With the seat out clean the passage way with carb cleaner. Now you must find a drill bit slightly smaller than the passage way, to be used to press in the new seat. Apply a very, very small amount of a very light lube to the new seat. 3-1 oil or lighter, to help seat it better. Carefully insert the new seat in the passage way with the rings on the seat down toward the carb body. Slowly and carefully force the seat down with the back end of the drill bit. Once it is seated, check to see that it did not flip and the rings are up. *Next check to make sure that the float does not have any liquid in it. *If it does, replace. *If everything looks correct, attach the new needle to the float and install with the float pin centered. It everything is correct, the float should seat level to the carb body, when looking at it upside down. If everything looks good reattach the float bowl, making sure that both the bowl gasket and the nut gasket seal properly. Reinstall on the engine and test unit. Remember to have patience and take your time. Good luck, but I don't think you'll need it.

PS: *On the side of some Tecumseh carbs you will find a plastic cover. *Under this cover will be an idle jet. *Remove it and check to see that the jet is open both horizontally and vertically. *You should be able to push the old float needle wire through the vertical opening.