Mower can not start

Mulan001

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I have a lawn-boy, model# 10670c, which can not start.
I changed oil, spark plug this spring. It worked well. 3 weeks before, it sill worked well. But now, it could not start. I cleaned carburetor, replaced with new air filter. Still cannot start it.
Recently, I bought a new ignition (34443D, solid state ignition). After installation, it still can not start. What else I can do? Please help.
 

Mulan001

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Mower can not start - 10670c model

Merged two threads.
 
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MowLife

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Just what he said and add correct timing into the mix.
 

Rivets

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Time to clean and rebuild the carb using this kit, 631021B, about $5.00. Here is the procedure I use.
[FONT=&quot][FONT=&quot]Needle and seat replacement.[/FONT][/FONT]
[FONT=&quot][FONT=&quot][/FONT]
[/FONT]

[FONT=&quot][FONT=&quot]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.[/FONT][/FONT]
[FONT=&quot][FONT=&quot][/FONT]
[/FONT]

[FONT=&quot][FONT=&quot]I would either give the carb a good 24 hour soaking or have it ultrasonically cleaned at this time.[/FONT][/FONT]
[FONT=&quot][FONT=&quot][/FONT]
[/FONT]

[FONT=&quot][FONT=&quot]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.[/FONT][/FONT]
[FONT=&quot][FONT=&quot][/FONT]
[/FONT]

[FONT=&quot][FONT=&quot]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.[/FONT][/FONT]
 

Mulan001

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Time to clean and rebuild the carb using this kit, 631021B, about $5.00. Here is the procedure I use.
[FONT=&quot][FONT=&quot]Needle and seat replacement.[/FONT][/FONT]
[FONT=&quot][FONT=&quot][/FONT]
[/FONT]

[FONT=&quot][FONT=&quot]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.[/FONT][/FONT]
[FONT=&quot][FONT=&quot][/FONT]
[/FONT]

[FONT=&quot][FONT=&quot]I would either give the carb a good 24 hour soaking or have it ultrasonically cleaned at this time.[/FONT][/FONT]
[FONT=&quot][FONT=&quot][/FONT]
[/FONT]

[FONT=&quot][FONT=&quot]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.[/FONT][/FONT]
[FONT=&quot][FONT=&quot][/FONT]
[/FONT]

[FONT=&quot][FONT=&quot]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.[/FONT][/FONT]

Thanks for reply. I used carb cleaner, bowl all the holes in every parts of Carb. I believe that the Carb is OK. I could not get the spark. why?
 

Rivets

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Let’s get this straight, you said you replaced the coil, never said no spark. Did you set the coil air gap at.010? Did you install it with the kill wire terminal down? Did you check the kill wire for frays or pinching? All these will cause a no spark condition. I replied as I did assuming that you set the coil properly. You said you cleaned the carb, but did you set the float as I described in the procedure? This will also cause a no start condition.
 

Mulan001

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Thanks for reply.
I replaced with a new coil bought in Amazon.ca. Using a business card to set the gap. connected the kill wire to coil just as before. Pulling many times, no any sparks. Then I suspected that coil I bought is not good.
I measure my old coil, set resistance range in 20K, High to Kill wire read 2.9. Looked like my old coil is OK. Now I am totally confused what make it not generate spark? Please help. Thanks.

Last night, I gave it a try again. Installed my old coil. took out spark plug, asked someone help hold it to the side of engine. Then I pulled, still no any sign of sparks.
 
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H20loo

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Thanks for reply.
I replaced with a new coil bought in Amazon.ca. Using a business card to set the gap. connected the kill wire to coil just as before. Pulling many times, no any sparks. Then I suspected that coil I bought is not good.
I measure my old coil, set resistance range in 20K, High to Kill wire read 2.9. Looked like my old coil is OK. Now I am totally confused what make it not generate spark? Please help. Thanks.

Last night, I gave it a try again. Installed my old coil. took out spark plug, asked someone help hold it to the side of engine. Then I pulled, still no any sign of sparks.

Disconnect the “kill wire” and check for spark. Clean the flywheel..

Thanks Rivets for that in-depth review. I copied it because I try to cheat sometimes and you covered all the bases.
 

Rivets

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Ok, let’s go back to the beginning. Checking resistance on today’s coils will not result in an accurate test, due to the primary circuit containing the trigger coil. First, I don’t care which coil you test first, but I would like you to install a coil without the kill wire attached and check for spark. If you have spark the coil is good and you have a bad kill circuit. If no spark and you know the coil is installed correctly, the coil is bad. Repeat using other coil. The test for a bad kill wire is check resistance from terminal which connects to the coil and ground. Do this with the brake bail handle tied back to open the kill switch. Your resistance reading should be infinity. Any other reading indicates that the wire is grounding out with the kill switch open, causing your problem. Do all tests with a new plug. I will not be around much for the next 5 days, so if you have other questions feel free to ask and I’ll try to get back to you ASAP, but I know other techs are following this thread and may jump in. Many times we don’t like to jump on other techs threads, because it can get confusing for the original poster. Hope your next post is saying success.
 
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