Toro mower starts after priming dies right away

Hi and welcome to FixYa. I am Kelly.
This is how to clean the fuel passages in the carb.
Here is what you need to do:

1. Fuel selector off
2. Remove float bowl mounting screws and nut
3. Remove the BRASS Jet / Orifice in the very bottom of the venturi tube inside the pickup tube. (Flat blade screwdriver) Hold the Orifice up to the light. You should see a pinhole. If it is not clear clean the orifice but do not force anything through the hole.
4. Underneath the Orifice there is yet another BRASS tube that you need to remove. (Flat blade screwdriver) Make sure all of the holes in the tube are clear. The tube will be over 2 inches long. Clean it and reinstall it.
5. Reinstall the Orifice.
6. Using a catch fuel container turn on the fuel selector. Fuel should flow at a good rate. GENTLY lift the float assy level and make sure fuel flow shuts off. When you drop the float again fuel should flow.
If you do not have fuel flow at this point the needle and seat will need to be inspected. Fuel selector OFF.
(The following procedure is to be done only if there is no fuel flow with fuel selector on.)
a. Remove the silver float pivot pin retaining screw
b. Drop the Float down (The needle will come off with the float. NOTE the position)
c. Inspect the tapered rubber of the needle If should be pointed. If it is not pointed then the rubber tip is stuck inside the seat.
d. Clean the seat hole ONLY if obstructed. (Easily damaged)
e. FUEL Selector on then off fuel should rapidly flow through the needle seat.
f. Renistall Float and needle making sure to get the pivot / hinge pin installed correctly and reinstall the silver retaining screw.
g. Fuel selector ON. Raise and lower float checking for free movement and fuel flow.

7. If there still is no fuel flow at this point remove the fuel hose from the carb and check fuel flow. If no flow check that gas tank exit hole, fuel filter (if installed) and the selector valve assy for obstructions. Reassemble connections.

FUEL FLOW IS GOOD

8. BEFORE you install the float bowl inspect the bowl nut. There are 2 holes in the side of the nut where it screws in to the bottom of the carb that must be clear.

9. Install Float bowl mounting screws and nut. Check for leaks.

10. Test engine.

That should do it. (carb cleaning 101)

Thanks for using FixYa.

Kelly

P.S. If it still does not start and you have a primer bulb on the carb the primer bulb most likely has a hole in it. Press and hold the primer bulb CLOSED against the carb inner mating surfaces and see if it will start. (2 people required) If it starts and runs the primer bulb has a pin hole in it.