Of course, answer the questions above about smoke color. The fact that it runs without the kill wire connected but not with it connected indicates that most likely the Interlock is bad. Typical. Of course it could be other things but this is the best odds. I haven't bought one for a long time, were about $15 then and of course are a Safety Feature, think liability. The smoking could be it is just plain worn out, cylinder scored, ring/rings broken, breather bad, or all of above (grin) Do you have a way to check the compression? When you spin the flywheel backwards by hand, does the flywheel rebound forwards quickly? Before you do anything drastic, remove the carb float bowl, clean it, check that the main jet going up inside the well that protruding down into the carb bowl, is tight. Is the float about parallel with the float bowl boss, seat, on the carb when the float is closed? Clean the float needle. Re-assemble, start the engine and turn the main jet adjustment screw, extending down out of the bottom of the float bowl, turn it counter clockwise slowly, does this help the rough running? Turn until the engine starts to stall or surges, turn clockwise until the engine falters, split the difference. Do the same with the Idle Mixture screw on the side of the engine at low speed. Next I would check the crankcase breather valve. I won't go into that here, email me if you want instructions. Walt Conner wconner5 at verizon dot net

Non: It could be a Weak Ignition / Coil Module . If the Dealer does indicate so and your purchase is over 30 days ago be sure to get yours back , identify it 1st so you know it is actually yours. I would rather think that the Carburator has become fouled a 30 minute or less job for the Dealer to correct . If he is reputable he will do so free of charge . If not I would be suspect . If he states both Coil and Carb Related issue I would be very Leary of his Ethics . If you have had the unit less than 30 days get your money back unless everything is corrected No Charge !

What exactly does the "interlock module" do? I have a mid 90s Broadmoor and the last time I tried to use it just the other day, the PTO wouldn't engage. I checked out the switch and it was OK. Pulled all the modular plugs apart in the wiring harness, cleaned the contacts which were crudded up with dirt and re-connected them. Finally, with the ignition on, when I engaged the PTO switch I could hear the solenoid engage normally, but I heard a hissing sound and what smelt like burning electronics. Then I noticed smoke coming out of the interlock module, and a putrid smell like a burning selenium rectifier or carbon resistor. The book says the interlock module is "untestable". I haven't checked on the cost, but I suspect they are expensive, and I'm afraid if I just buy a replacement and stick it in, and the electrical problem is elsewhere, the new one would burn up too. I took the interlock module off and cut a hole in the case where the plastic had melted and smoke was coming out. All I could see inside was some kind of substrate and the rest of the case was full of what looked like whitish sand. I poured out all the sand, replaced the module, and re-started the tractor. It started up OK (it won't start with the module unplugged from the cable). When I turned on the PTO switch, it engaged normally, and there was no more smoke from the module. The only thing abnormal now is the PTO light gets extra bright for a split second just when I switch the PTO off; I don't remember it doing that before. Does anyone know exactly what is inside the interlock module and exactly what it's supposed to do in the circuit? The schematic just shows a rectangle with numbers on the pins. The mower seems to work OK now, but I don't want to burn something else up running it with a defective interlock module.

I'd check that the choke butterfly is not stuck closed. This is what happened on mine, Sears lawn tractor 917.275371, Engine Briggs & Stratton 31C707 type 0230-E1 (31C7070230E1) I sprayed carb aerosol cleaner on it, noticed that the choke would not open, so it was running real rich. I ended up drilling a small hole in the red palstic motor housing and attaching a spring from that hole to the already-there hole in the black lever on top of the carb, the lever which actuates the carb butterfly. Pushing the throttle all the way forward closes the choke for starting, but the internal spring to open the choke is too small, or some have posted that the shaft is too large and that one should take it out and shave it a little smaller. The added spring works for me. Sorry, I don't have a photo yet, the lawn tractor is 100 miles away.