MTD Yard Machines Mower Stalls When Clutch is Let Out?

[Mike Correll]

I have an MTD Yard Machines lawn tractor with a 12.5 hp Briggs and Stratton engine. I've been working on it quite a bit, fixing things here and there. I have one issue that's keeping me from finally getting to use it again. When I try to release the clutch on this tractor, the engine stalls out every single time. I can start it and let it run just fine, but when I try to move either direction it shuts off. This tractor has a brand new battery, starter solenoid, and spark plug. I've also recently cleaned the carburetor once or twice. I have a feeling there is something wrong with a safety feature somewhere... but if anyone could give me some advice on how I could target and fix this, it would be greatly appreciated. :smile:

 

[bertsmobile1]

If you have an electric clutch try to engage the clutch.
If the clutch does not engage, then try again with the engine running.
If the engine cuts out you have a problem with the seat switch not activating.

 

[willys55]

a quick test would be to unplug the seat switch and put a paper clip into the connector, open the paper clip up and shape it like a tiny harp and slip it into the connector, make sure the machine is in neutral and start it up and engage the clutch, if it works then replace the switch.

 

[Mike Correll]

I've messed around with the seat switch quite a bit today... I also noticed that I can engage the pto and that works fine. Still Im not able to move the tractor. I'm scratching my head at this problem. This tractor doesn't have one of those little plastic button things as a seat safety switch like most do. Instead, it has two little metal tangs under the left front corner of the seat. The metal tangs touch when there is weight on the seat. They separate when there's no weight. There are two yellow wires hooked to two terminals on the switch. One wire has a black line. I've unplugged each of the wires, both of them at the same time, and I removed the switch completely. It still has the same issue.

 

[willys55]

did you connect the two wires together without the switch?

 

[Mike Correll]

did you connect the two wires together without the switch?

I had them touching together and tried letting the clutch out again. The engine is still cutting off.

 

[Mike Correll]

I've also noticed that the rear wheels lock up even if the parking brake is off and the tractor is in neutral. Makes it pretty much impossible to push it anywhere.

 

[Mike Correll]

UPDATE: So I found the problem and fixed it. Kind of.... it turns out the problem is/was in the clutch switch. As long as the plunger is depressed, the mower can move. But, since the clutch being engaged depresses the plunger AND applies the brake, the mower would stall because it thinks it's trying to be driven with the parking brake on. I tested this by taping the plunger down. Now I can drive the mower as long as the plunger is taped down. The tape keeps coming off though, so I'm going to take the switch off and find a way to keep it pressed in.

 

[bertsmobile1]

OK,
You get the Sherlock Holmes award this week.
The brake/clutch switch should have larger holes than the mounting screws or slots in it to allow for some adjustment.
Otherwise replace it they are quite cheap.
Take it to a mower shop to get a replacement because there are a few variations and they all look the same externally