no spark

[Anonymous Poster]

can someone help me track down my no ignition spark problem? I have a Craftsman 18 hp garden tractor. It was running fine until I flipped the mower-deck switch to on. Then the whole thing just quit. I think I have a bad safety switch somewhere, but there must be a half dozen of them. Any suggestions on how to start?

[Bird]

Don't know just which model you have, but I'd suspect a fuse instead of a switch. If you turn the mower deck switch off, will the mower engine start again or not?

[Anonymous Poster]

If it happened when you engaged the deck belt then I would check the deck switch first. The only requirement I know of concerning the deck is that an operator has to be in the seat and not moving in reverse to run the blades.

[grainger12002]

these can be tricky because some act as a ground to complete the circuit-

[markie61]

Last time it happenend on my wife's "little tractor", it was the seat safety interlock. I drove it last and when she adjusted the seat forward, it pulled slightly out to the snap connector (not enough to see, but it "clicked" back when I pushed on it and then started.)

Mark

[Anonymous Poster]

Got some new info. Last night after I checked that all the interlock switches were worknig, I was trying to start it again and noticed that there is some random spark at the plug. There is more spark, however, between the frame and the parking brake (steel) lever. I assume that there is a short somewhere, but how do I find it?

[kubmech]

Depends on the make and model of the 18 hp engine you have. In the past I have seen the throttle cable/choke cable grounding out on the hot side of the coil lead causing arcing in interesting places. That is if you have a 12 volt ignition system and not a typical magneto ignition system. In the 18 horse range I know Kohler and Onan use a 12 volt system on there twins. Is the engine mounted on rubber isolaters? Most engines mounted in this way should have a seperate ground strap from the engine to the frame. Other wise the engine components will ground through whatever means is available, which is usually the throttle/choke cable.