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Black soot from new lawn mower?


pazgb's Avatar
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Join Date: Aug 2005
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08-16-05, 07:57 AM   #1  
Black soot from new lawn mower?

Hello All,

I bought a new sears craftsman 6.75hp ez-start lawn mower a couple weeks ago. I used it a couple times and the engine is producing a black soot all over the deck and all over my new white bag(which is now black!)

I started looking around on the Internet for answers and no suck luck. I read a couple articles but I do not know how realiable they are.

One mentioned adjusting the carb because it might be overly rich mixture?

The model I have you cannot adjust the carb.

http://www.sears.com/sr/javasr/produ...ear+Bag+Mowers

If anyone knows, please let me know.

Thanks,
Mike


Last edited by pazgb; 08-16-05 at 08:15 AM.
 
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dave237's Avatar
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08-16-05, 08:35 AM   #2  
pazgb,

Welcome! You're correct. they are no mixture adjustments on this carb. Sounds like the choke flap is not opening all the way. This will cause a rich condition. Being this engine is only two weeks old I would return it to Sears for a swap!

God Bless,
Dave237

 
Azis's Avatar
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08-16-05, 12:31 PM   #3  
Azis
It does sound like the engine is flooding, and since you have no throttle control, or choke control, and the add boasts "No Prime" needed...I am curious as to what they have done for starting and if it is going to have a common failure....
since it is only 2 weeks old I would do just as dave237 suggested.

 
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08-16-05, 02:45 PM   #4  
You didn't provide a model number of the machine but i'll guess this has the new Briggs "One-Start" engine whereas it has an auto-choke feature. No priming or no choking is required to start these. I've only seen them on paper at the last factory service school and don't know much about them as I haven't seen one come in our shop for service. The black "soot" you have, is this exhaust soot or actually excessive oil blowing all over by way of the exhaust pressure? Does the film feel powdery or wet? Perhaps you have the engine overfilled with oil and you're getting oil spewing from the muffler and coating everything in sight? Post back with these answers as well as the chassis ID #'s along with the engine ID #'s.

 
pazgb's Avatar
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08-23-05, 09:28 AM   #5  
puey61,

You are correct about the one-start model. I included a link to the mower in my first post. Since my last post I returned the mower and exchanged with the same model. I cut my lawn 2 days ago and the same thing!

Black soot all over the deck.

I followed the instructions about adding the oil even though the quick start guide and the operating manual contradict each other. The quick start guide says add oil while checking the dip stick. The operating manual says add whole bottle of oil(the one that comes with the mower). That didn't seem right so I put about half the bottle in which is right in the middle of the empty and full line on the dip stick.

The black soot is more wet then dry. Its Not like a powder. You need to wash your hands not just brush them off.

Any Ideas let me know, otherwise im just going to return it again and buy a different mower with a different engine.

Thanks,
Mike

 
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08-23-05, 02:25 PM   #6  
This is a difficult diagnosis on my part since I can't see the machine. But, fill, but do not overfill, the oil based on the reading on the dipstick. This engine, if I'm not mistaken, holds 20 ounces of oil. You need to screw in the dipstick in order to acurately read the oil level. Again, make sure it is not overfilled. Also bear in mind that extreme running angles can cause oil to make its way into the muffler and spew it out all over the deck. If you continue to have the same problem, I suggest taking it to a local authorized Briggs dealer for their inspection and diagnosis. As of today, I have received no Briggs Service Bulletins on this engine so I know of no known service issues with it.

 
pazgb's Avatar
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08-23-05, 02:29 PM   #7  
Now that you mention it I do have a small decline in my back yard but it is nothing huge. It drops like 10 feet all the way from the begining of the backyard to the end.

I think Im just going to return it and buy a different mower and engine that does not have the all-in-one.

Thanks,
Mike

 
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