# Engnie dies when blades engaged.



## Maytag (Dec 10, 2007)

I have a friend who has a Craftsman rider (42") with 15.5hp Kohler that dies when the blades are engaged. I read in an old post about disconnecting the engine kill wire to isolate the engine to troubleshoot. Makes sense. If that shows the interlock system to be the issue, what would the next step be please? The seat switch has been pulled already for some time (year?) so it would "seem" that is not part of the issue. By that I mean the present issue would have surfaced before this if the seat switch was part of the problem. Unless a wire from it got pinch or something? That would leave the blade "engage" switch and.......?


Thanks in advance for any help.

>Maytag


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## 30yearTech (Sep 14, 2006)

If the engine will run when the clutch pedal is released then it's not in the seat switch circuit. The seat interlock will cause the engine to die when the clutch/brake is released or the blades are engaged, if there was something wrong in the seat portion of the interlock.

Try engaging the blades with a little choke, this will tell you if the engine is stopping because it's not getting enough fuel to carry the load, also make sure everything on the mower deck is moving freely and there are no seized bearings or spindles.


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## bgbass (Jan 11, 2008)

If everything 30 year said checks out ok there is a wire in rear that plugs into trans. unplug and see it it fixes problem


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## 30yearTech (Sep 14, 2006)

bgbass said:


> If everything 30 year said checks out ok there is a wire in rear that plugs into trans. unplug and see it it fixes problem


Wire in the transmission?? 

I have never run across this on a Sears unit, or any that I can think of. What does this wire do? and where does it plug in at?


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## bgbass (Jan 11, 2008)

Hi 30 year I just had one doing this on a craftsman tractor it plugs into the trans. if you look from the rear you will see the wire plugged in its a safety switch to the mower so you cant go in reverse with mower running the one I had would die every time i tried to turn mower on I unhooked wire and it worked fine. The only thing is that now you can go into reverse with mower running if there was little kids around i would have put a new switch in but there is no kids around so i left it unhooked. Im not sure if the switch shorted out or stuck.


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## 30yearTech (Sep 14, 2006)

Interesting, I have seen something similar on MTD units, but on the linkages not the transmission. Do you happen to have the model number of the unit you saw this on, I would like to take a look at the IPL and see how it works.


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## bgbass (Jan 11, 2008)

Hi 30 year I have a mtd model# 13af608g062 they also have them on the toros, cub cadets and im sure others its just a safty switch and when it screws up the tractor wont go into reverse the mower will kill the motor when turned on ect. Its desinged so that if you have the mower on you cant put tractor in reverse or the engine dies. mike


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## glenjudy (Aug 26, 2006)

I have seen the wires on the xmission on old, old Craftsman 3 speeds, seems to be a neutral (or not neutral) switch.


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## 30yearTech (Sep 14, 2006)

bgbass said:


> Hi 30 year I have a mtd model# 13af608g062 they also have them on the toros, cub cadets and im sure others its just a safty switch and when it screws up the tractor wont go into reverse the mower will kill the motor when turned on ect. Its desinged so that if you have the mower on you cant put tractor in reverse or the engine dies. mike


I am aware of the reverse interlock on the shift linkage on MTD manufactured riding mowers, which is what the model number you posted shows. 

I was actually interested in the one you described on the Sears unit that had the wire on the transmission. Most Sears riders are Husqvarna units and some Murray RER's. I was trying to find info on any switches directly in the transmission.


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## Maytag (Dec 10, 2007)

Thanks guys for the responses. So far the owner has removed the kill wire from the engine and he was able to cut the grass without further problems. He was fully aware that the "safeties" were disabled. He's going to check backwards further and see if there is a bare wire to ground or something with the blade switch causing it to kill the engine when he engages the blades.
I haven't looked, but how is the blade kill switch configured? Normally closed or open with blades off ? Is it SPST or DPST or what?

Thanks,

Maytag


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## 30yearTech (Sep 14, 2006)

Depends upon the specific model number of the rider. Most use a plunger switch that interlocks both the starter and the engine. There is usually a black (ground) wire that "closed" when the blades are engaged, and a white (starter solenoid Hot) wire that is closed when the blades are disengaged, same for the clutch. The seat switch is open when engaged and closed when disengaged, there is also a sensor in the plug going to the seat switch that will close the circuit if the seat switch is unplugged, this will prevent the the unit from operating without a good seat switch or if the switch is jumped.


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## Maytag (Dec 10, 2007)

Thanks 30yearTech. Haven't heard any results yet, but you've helped him figure out how to approach the troubleshooting.

>Maytag


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