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mower won't start


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04-11-09, 10:17 PM   #1  
mower won't start

I'm not really thinking my problem can be diagnosed through a thread, but figure it never hurts to try. Keep in mind, I'm no guru.

A friend asked me to tune up her mower. It's a walk behind craftsman mulcher with a briggs engine. I went to remove the blade first so I could get the oil draining and saw that the blade was BADLY bent, so took it off and the adapter was broken too. (someone gave her this mower) So, with blade and adapter off, (believe it or not the shaft looked okay) I tried to start it just to see if it would start, and it started. I only let it run about 30 seconds and since it started felt safe in buying a new blade and adapter. I put the new blade on, changed the oil, spark plug and filter. Tried starting it and nothing. It has spark. So, bought a carb kit and cleaned it out. Also removed the primer bulb and blew dirt out of the screens. Still would not start. Long ago someone told me to spray wd40 in the carb if a mower wouldn't start and if it ran on the wd40 but then died, it meant the carb wasn't getting gas. It will not even run on the wd40. Nothing. I'm really baffled since it ran before, even though I only let it run for a few seconds. Since it had run I did not replace the welch plug. Not really sure if that would really make a difference but thought I should mention everything I've done and haven't done. Any guesses or suggestions? Thanks for reading!

 
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04-12-09, 04:04 AM   #2  
Most likely a sheared flywheel key. I would be surprised if it is not sheared with a broken blade adapter. You can inspect key by removing flywheel cup and looking to see if key is centered in crank keyway. Best to remove flywheel to inspect

 
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04-12-09, 02:16 PM   #3  
Thanks smallengineguy. I actually thought of that but figured since it started a couple of days ago that wouldn't be it. But, I'll certainly look at it. Is there any way to pull the flywheel without a puller?

 
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04-12-09, 04:43 PM   #4  
I agree, flywheel key. Pull the flywheel nut and look at the slot in the crankshaft and flywheel and see if they're lined up. If not, the key is sheared.


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04-27-09, 02:51 PM   #5  
Okay guys. I finally borrowed a flywheel puller, and for whatever reason the flywheel cracked. #@!%&* So, I finally located a used flywheel, replaced the key which had a slight crack in the side of it but wasn't what I would consider sheared, put it all back together, and still nothing. Nothing at all. Any other suggestions?

 
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04-27-09, 11:41 PM   #6  
Try putting about a tablespoon of gas into the spark plug hole and see if it fires up. If you have spark, compression, and fuel, it should do something.


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04-28-09, 05:26 AM   #7  
I'll try that tonight Cheese, thank you. I was laying in bed last night wondering about compression.

 
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04-28-09, 05:56 PM   #8  
Alrighty! We have ignition!! LOL It did start when I put the gas in the plug hole. I let it run for about 5 minutes. Blew white smoke at first but then that stopped. Now, I'm not sure what this means. Of course now every time I pull it, it starts since it's warm, so I guess I'll try starting it again tomorrow night the conventional way and see what happens. If it doesn't start tomorrow, what would you guess the problem to be? Carburetor, even though I cleaned it and replaced all but the welch plug? With any luck it just needed some coaxing and will start every time now. LOL Pie in the sky dreamer I am!!!!! Thank you for your help guys!!!

 
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04-28-09, 10:07 PM   #9  
Take the air filter out and look into the throat of the carb while priming the primer. Do you see gas pumping up into the center of the carb throat? If not, replace the gasket between the air filter housing and the carb. This should solve the problem.


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04-29-09, 05:25 AM   #10  
I will look at that tonight, but I did replace that gasket when I cleaned and put a new carb kit in.

 
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04-29-09, 06:59 PM   #11  
Didn't see gas in the carb Cheese. Removed the air filter housing, and somehow I managed to tear the gasket when I put it on. I'll be getting another one tomorrow!!! Thanks for all the GREAT advice!!!!

 
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05-02-09, 09:40 AM   #12  
Well, replaced the gasket and made sure it went on properly but the primer still won't pull gas into the carb. Primer appears to be working properly. What do I need to try now Cheese?

 
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05-02-09, 06:51 PM   #13  
The primer pumps a small amount of air into the carb bowl, which pressurizes it, forcing a bit of gas up the nozzle into the throat of the carb to prime the engine. If there is a little leak allowing air to escape, it will not prime. The gasket between the carb and the bowl gasket are the only 2 seals related to this part of the system. I'd check the owl gasket and see if it's bad or out of place.


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05-04-09, 05:33 PM   #14  
Okay Cheese. The air filter gasket is good. When I removed the carb the float bowl gasket seemed loose to me so I went and got another one even though it was new. The new one fits snugly. I made sure a pin went thru the nozzle and it did so there's no blockage. Well, it still won't prime. Any other suggestions? Based on what you've said so far, I'm baffled that it won't prime.

 
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05-04-09, 07:42 PM   #15  
The only other problem I'm aware of at times with these is that sometimes the air filter housing warps and doesn't seal well between the housing and the carb. Sometimes 2 gaskets stacked together works, but sometimes you just have to replace the back part of the housing. Other than that, I don't know what to tell you. Push the primer really fast and fully depressed, and watch the nozzle sticking up in the carb. Will it pump any gas up at all with the vigorous prime?


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05-05-09, 05:28 AM   #16  
I'll try that tonight but I will tell you that it DID prime before I replaced all the gaskets and cleaned the carb because I started it once before replacing the blade and all. And I did SEE the gas come up thru the nozzle at that time so I can't imagine that the housing would be warped. After all the money I spent to fix this mower, I just can't give up now!!! I am going to try holding my tongue all different ways when I try it tonight!!!!!

 
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05-05-09, 03:07 PM   #17  
Okay Cheese. I tried the vigorous prime, and can't do it because the primer bulb doesn't come back fast enough. I have to wait a few seconds before it comes back to prime again. But if I do what I would call a normal rate prime on it, the bulb comes back fine. But, still no gas coming out of the nozzle. Guess I'll spend 3 more dollars and try the double gasket thing and see if that helps at all.

 
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05-05-09, 05:39 PM   #18  
There is a passage in the carb body that the primer pumps air through as cheese has described. Check this passage to make sure its clear.
Since your primer bulb will not return as it should, I would guess a restriction somewhere and the gaskets are sealing well enough perhaps.

 
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05-05-09, 07:33 PM   #19  
Look on the back side of the filter housing where it fits on the gasket. You'll see a small channel behind the gasket where the primed air goes. It goes along under the opening up the side to a small hole. Make sure there is a hole in the gasket at this same spot. Make sure this also aligns with the hole in the side of the opening in the carb.


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05-06-09, 03:30 PM   #20  
I checked the hole in the gasket. It matches both the housing hole and the carb hole. I blew air into the hole in the carb and it shot gas thru the nozzle. I removed the primer bulb and made sure all that passageway was clear. The only thing I noticed on very close inspection of the filter housing that I hadn't before, was that there is a small hairline crack above the bolt hole that is above the gasket hole. Could this crack be causing the problem? If so, would a second gasket fix that or would I HAVE to buy a new housing? I'm just trying to avoid spending any more money on this mower.

 
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05-06-09, 10:44 PM   #21  
That is probably the cause of the problem. Everything else has been ruled out. A crack in that part is almost definitely a problem... they sometimes don't seal well even without cracks. Go to your local small engine shop and pick up a used one. You should be able to grab one for $5.


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06-16-09, 02:04 PM   #22  
Well, I never could find a used filter housing, nor could I even find a new one that didn't have to be ordered, so I went ahead and bought a second gasket and it primes like a charm now!!!! Thank you so so so much for all the GREAT help!!!! Stay tuned. I put my used self propel Snapper together and though it looks like it's working just as it should, it doesn't self propel. Think I'm going to just take it into the shop though. Any way, again, thank you for the help. I am amazed that you can fix a mower over the internet!!!!

 
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