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MTD Yard Machine Lawn Mower Loss of Power


Muka1234's Avatar
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07-27-09, 01:48 PM   #1  
MTD Yard Machine Lawn Mower Loss of Power

Hi,
I have a MTD Yard Machine Self Propelled Lawn Mower and the mower was working fine until yesterday when I started to notice a drastic loss of power. The mower would move very slowly and I can tell from the sound that the engine is losing power. Seems like the motor is spinning very slow and I have to manualy push the mower to move forward as the self propelled option is not helping.
Some info on my mower
Briggs & Stratton Engine Model # 12H802, Type 2672-E1, Code 9803065
Yard Machine by MTD Model # 12A-379N062

Thanks for any help.


Last edited by Muka1234; 07-27-09 at 04:02 PM.
 
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07-27-09, 08:21 PM   #2  
Did it happen to occur about the same time you pushed it under some bushes or something like that? If so, the little tab that the governor spring hooks to at the right front corner of the engine over the carb got bent backwards some. Pull it toward the front of the engine some to increase speed if this is the case.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

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07-28-09, 04:31 AM   #3  
Thanks for replying Cheese.
I don't remember hitting any bushes or trees as my yard is kind of bushless but I did noticed that when the engine is running and I pulled the little tab that is attached to the thin spring (not sure if this is the govenor) towards the back of the mower the engine rev and increased but when I release it the engine speed goes back to normal. Is there any way to permanently have the tab at the higher rev position? Thanks again for your help.

 
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07-28-09, 04:49 PM   #4  
Posted By: cheese Did it happen to occur about the same time you pushed it under some bushes or something like that? If so, the little tab that the governor spring hooks to at the right front corner of the engine over the carb got bent backwards some. Pull it toward the front of the engine some to increase speed if this is the case.
Thanks Cheese. You suggestion worked great.
Thanks again

 
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07-29-09, 12:45 AM   #5  
Glad we could help! Thanks for the update!


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08-01-09, 07:32 AM   #6  
Follow up

Here is a follow up to my earlier response. I used th mower to mow the lawn yesterday and I did noticed that it started out with lower power that usual but I continued to use it and then suddenly (about 20 minutes after initial startup) the mower started to rev at a higher speed. I noticed that the lever that is attached to the govenor spring was moving forward and backwards causing the mower to rev at a higher speed. After about another 10 minutes the mower cut-off because the gas tank was empty. This is very strange because prior to starting, I filled the tank and it never used up a full tank to mow the lawn once. This is telling me that the mower is now using more gas than before. Also after it cut off, I filled back the tank and it did not started back after I had to let it sit for a half hour. After it started back its still working with lower power than usual. Not sure what to do now. Any help is appreciated.
Thanks

 
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08-01-09, 08:31 AM   #7  
Have you kinda checked it for a tune-up??? Make sure the air filter shows light thru it & make sure there is no signs of it getting wet... Check the plug & next time it won't start check for spark.... Is there any chance you hit something??? The flywheel key may be partially sheared.... Does it leak any fuel from the carb if it sits for several days ??? Check it out & let us know what you find.... Roger

 
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08-01-09, 02:27 PM   #8  
Posted By: hopkinsr2 Have you kinda checked it for a tune-up??? Make sure the air filter shows light thru it & make sure there is no signs of it getting wet... Check the plug & next time it won't start check for spark.... Is there any chance you hit something??? The flywheel key may be partially sheared.... Does it leak any fuel from the carb if it sits for several days ??? Check it out & let us know what you find.... Roger
Hi Roger,
Thanks for reply and I will try to answer all your questions.
1) No, I have not checked if for a tune-up (not sure how to do this) but I did changed the air filter about a month ago when I had to replace the pull-string for starting. I checked the filter and its clean and no sign of wetness.
2) I changed the plug last saturday when I noticed loss of power and I thouht it might be a plug problem (Correct plug installed)
3) I don't remember hitting anything but how do I check if the flywheel key is not damaged.
4) I don't see any fuel leaking from the carburator just some dirt around the governor/lever/spring and I cleaned it with breaks cleaner. Not sure how to check for leaks in the carburator but I don't see any fuel leaking on the floor.
Thanks again for your help.
Kris

 
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08-01-09, 04:44 PM   #9  
Kinda sounds like you have most of it covered... When you had to replace the pull string,, Was it trying to pull the starter string from you're hand when starting it??? To check the flywheel key,, remove the fan cover & the starter cup... If the slots in the crankshaft & the flywheel aren't lined up perfectially,, Than the key is sheared.... Roger

 
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08-02-09, 07:47 AM   #10  
Posted By: hopkinsr2 Kinda sounds like you have most of it covered... When you had to replace the pull string,, Was it trying to pull the starter string from you're hand when starting it??? To check the flywheel key,, remove the fan cover & the starter cup... If the slots in the crankshaft & the flywheel aren't lined up perfectially,, Than the key is sheared.... Roger
Thanks again Roger for your response
The string was broken so I had to replace it.
The slots in the crank and flywheel looks lined up to me. Like I said in one of my earlier responses the engine was running at a high rev for about half hour during which I noticed that the governor lever that is attached to the governor spring was moving back and forth while I was mowing and it caused the engine to work at a higher rev so it did not make the engine seems to wanting to stall and it was cutting the grass and fine. The only thing noticeable was the high amount of gas it used as I had to refill the Tank where as I never had to refill the tank for mowing the yard once. Now that the governor lever is not moving back and forth, the engine is working at a low rev and is wanting to stall during mowing. Do you know if the governor lever is supposed to move back and forth when the engine is running? I think its something to do with this but not sure.

 
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08-02-09, 11:14 AM   #11  
No, the governor should not be constantly moving.


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08-03-09, 06:51 AM   #12  
Posted By: cheese No, the governor should not be constantly moving.
Hi cheese,
Thanks for replying. Any suggestions on what next?

 
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08-03-09, 10:49 PM   #13  
Look into the carb throat to see if the throttle butterfly valve came loose from the shaft.


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08-04-09, 04:25 AM   #14  
Posted By: cheese Look into the carb throat to see if the throttle butterfly valve came loose from the shaft.
Thanks for your suggestion cheese.
Will try this. Any suggestion how to get to the carb throat/throttle butterfly?

 
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08-05-09, 12:05 AM   #15  
Take the air filter housing off so that you can look into the opening in the carb. You can see the brass throttle plate in there and a screw or 2 should be holding it to the shaft.


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08-10-09, 06:27 AM   #16  
Posted By: cheese Take the air filter housing off so that you can look into the opening in the carb. You can see the brass throttle plate in there and a screw or 2 should be holding it to the shaft.
Well I've exausted all suggestions and the engine is still running with none to little power. No problem starting but no power in the engine. Any way thanks for all who have given their input. I think its time to pack up the old Yard Machine for a new one.
Kris.

 
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