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A lady gave me a yard machine push mower with a 650 series briggs and stratton engine with auto choke and it won't start , I have cleaned the gas tank and pulled the carb off and cleaned the gas bowl and used compressed air on all passages and cleaned needle and seat also put new spark plug on this engine has good spark. Before i did this the only way it would try to start was with starting fluid. Is ther something i am missing?

Catfish2 said:

A lady gave me a yard machine push mower with a 650 series briggs and stratton engine with auto choke and it won't start , I have cleaned the gas tank and pulled the carb off and cleaned the gas bowl and used compressed air on all passages and cleaned needle and seat also put new spark plug on this engine has good spark. Before i did this the only way it would try to start was with starting fluid. Is ther something i am missing?

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Did you clean the air filter? Is there something tied around the blades, preventing it to start?

God I hate non-adjustable carbs on those engines.

Two things with the auto-chock. One, is the choke closing when closed? Two, when you had the carb apart, did you check to see if the float level was set slightly rich?

Rivets said:

Two things with the auto-chock. One, is the choke closing when closed? Two, when you had the carb apart, did you check to see if the float level was set slightly rich?

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The choke is closed, and a stupid question how do you check the float to see it is rich and how do you adjust this . thanks

LazerZLandscaping said:

Did you clean the air filter? Is there something tied around the blades, preventing it to start?

God I hate non-adjustable carbs on those engines.

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Yes I replaced the air filter and it is easy to pull and it trys to start without starting fluid but just for a few seconds, I checked the safety kill wire no breaks and the ground is coming off the flywheel when handle is pressed, Thanks

Remove the carb and float bowl. Tip the carb upside down and look to see if the float is level. I set the float slightly rich, meaning the side opposite the pivot pin is slightly lower. Unless you have a plastic float, you should see a brass tang which the float needle is attached to. Slightly bending this tang will set the float richer or leaner. Here is my procedure for cleaning and rebuilding a carb. I always replace the float needle and seat, $3.50 is cheap a cheap solution to most carb problems.

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.