B&S (281707) Riding Lawnmower-Shuts off when blades engage

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  #1  
Old 08-31-10, 01:19 PM
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B&S (281707) Riding Lawnmower-Shuts off when blades engage

Hello,

I have a pretty old MTD riding lawnmower with a 12 HP Briggs&Straton engine on it. The engine works fine and everything and I recently rebuilt the carburetor so all is well in that department as far as I know. The problem I have is when the blades engage. Right when I release the lever for the blades, the engine starts to choke and shuts off. I thought there was something wrong with the bearings on the blades so I took the entire deck off but same problem. Even with the deck off, when I engage the lever for the blades it still shuts off. I tried to look and see what happens when the lever is engaged but I can't find any actually changes so I don't know what is happening underneath. I'm completely stumped and I hope someone can help. As I am sure I am leaving out some crucial detail please let me know and I will try to be as detailed as possible and help in any way I can. Thanks.
 
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  #2  
Old 08-31-10, 01:22 PM
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MTD should be a label under the seat with model and serial #.

Sounds like the seat switch is the culprit to me.
 
  #3  
Old 08-31-10, 01:40 PM
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It was really faded but here is what I was able to make out: 131650F000/ F1D1B4.

The safety switches never occurred to me . The seat switch on this mower shut of the engine if it is released so it can happen before the blades engage. That makes me curious as to whether that is the problem. Do you think there are other safety switches that could be the problem?
 
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Old 08-31-10, 02:19 PM
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Can you drive the mower without the blades engaged?
 
  #5  
Old 08-31-10, 03:03 PM
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Yes I can drive it without the blades engaged but once I engage the blades, it shuts off.
 
  #6  
Old 08-31-10, 03:52 PM
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I thought it might be the reverse safety switch but that has never worked. I did find two yellow wires that are connected together and they resemble the wires that are for the seat safety switch. I took the plate that covers the Reverse/ Neutral/ Drive shifter and found that this wire is supposed to be attached to it. I attached it and nothing happens and the same problem persists. Maybe I should try cutting these two yellow wires so they no longer make contact? Is there anyway to attach photos to our posts? Maybe that would help me explain.
 
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Old 08-31-10, 08:15 PM
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Originally Posted by msara0225 View Post
It was really faded but here is what I was able to make out: 131650F000/ F1D1B4.

The safety switches never occurred to me . The seat switch on this mower shut of the engine if it is released so it can happen before the blades engage. That makes me curious as to whether that is the problem. Do you think there are other safety switches that could be the problem?
check and see if there is another letter or number before or after the 1?
 
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Old 08-31-10, 08:27 PM
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Originally Posted by 38racing View Post
check and see if there is another letter or number before or after the 1?
Never mind I think I found it as you had it.
 
  #9  
Old 08-31-10, 08:37 PM
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Originally Posted by 38racing View Post
Never mind I think I found it as you had it.
go here
Outdoor Distributors - Lawn Mower Parts!

third one down is your parts pdf which has the wiring schematic.
seat switch has 2 yellow wires connected to it that get grounded when off seat. One is from PTO and one from clutch. Grounded will occur if off seat and pto is engaged or off seat and pto not engaged but brake/clutch out. Normally then if you remove at the seat switch the yellow wire coming from the pto then you override that safety feature that seem to be causing your problem. Trace the yellow wire from the pto switch and you'll likely find it grounded somewhere before it reaches the seat switch.
 
  #10  
Old 09-03-10, 01:00 PM
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Exclamation There's a saftey switch!!!

There will be a safety switch that opens when you engage the blades. It is at the bottom of the handle assembly. If wires are crossed out other places, then you're breaking the circuit by engaging that switch. I just put a zip tie around mine to keep it closed always.
 
  #11  
Old 09-03-10, 10:12 PM
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wondering if he got this fixed?
 
  #12  
Old 09-05-10, 02:31 AM
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Thanks for the pdf. Sorry i havent replied, I just moved into my university and havent had time to respond. I found the wires from the diagram but now a new problem has happened... the lawnmower doesnt want to start so i can't test if it worked or not. I wont be home for another week or so to work on it but if i do get it to work I"ll you guys know and i really appreciate the help guys. Thanks.
 
  #13  
Old 09-05-10, 06:26 AM
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the pto switch will have 2 sets of wires, one for the safety engine spark kill in conjunction with seat switch and other for starter circuit through ignition and clutch to starter solenoid. If a wire comes of the latter one then you'll get a no crank situation , like you had blades engaged while trying to crank
 
  #14  
Old 09-06-10, 08:28 AM
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It cranks but doesn't turn over so now I have to figure out what has happened... I sprayed some engine starter into the air filter and it turned over so I'm going to keep messing with it once I go back home for a weekend and see if I can get this thing going! Thanks.
 
  #15  
Old 09-07-10, 12:38 PM
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Originally Posted by msara0225 View Post
It cranks but doesn't turn over so now I have to figure out what has happened... I sprayed some engine starter into the air filter and it turned over so I'm going to keep messing with it once I go back home for a weekend and see if I can get this thing going! Thanks.
I assume you mean it cranks but does not fire. I consider cranking and turning over to be one and the same. Sounds like a fuel/carb problem
 
  #16  
Old 09-09-10, 08:54 PM
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Yes that's what I meant. I'm going to have to get it to start before I can for the problem with the blades now. It's one problem after the other but I guess that's the learning process. Thanks 38Racing.
 
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