Spark plug specification for: Yard Works 725EXI, model 104M020013F1, seri 1503185886898

Before you start doing anything around the deck area, remove the spark plug.
Depending on the model, it could be riveted or welded on. If you can't locate any bolts or screws it may not be able to be removed.

disassemble carburetor, soak in solvent, check the float, needle and seat, replace if necessary,,,using compressed air blow out all vents etc in carb body,,should take care of problem

It depends on the brand of spark plug being used, could be anywhere between .030" to .044".

for me .032"/.034" gets the best results, although some people get good results at .030".

You need to experiment a little & see what works with best with your vehicle.

Run some Sea Foam through the next tank of gas that may help

I would say if you can get a spark by moving the ground, try running the mower. If it works you should be OK.

Gary

http://www.mtdparts.com/webapp/wcs/stores/servlet/OperatorManualView?storeId=10101&catalogId=19502&langId=-1 that's where you can find your manual. Just put in your model number, and serial number too and your manual(s) will be accessible.

If this is a 4 cycle mower (seperate places for gas and oil) and you are using a oil and gas mix as I am reading from your post that is your problem. When you use a gas&oil mix in a 4 cycle you get smoke and if fouls your spark plug. Also be more specific where the oil and gas mixed is leaking from. I SUGGEST THAT YOU DRAIN OUT THE GAS&OIL MIX AND CLEAN THE SPARK PLUG OR REPLACE AND FILL WITH STRAIGHT GAS AND SEE HOW IT RUNS.

Good luck
roundo4

If your mower does not have "OHV", overhead valves. You can use a Champion j19lm spark plug.
If you discover you do have overhead valves; A Champion RC12YC, will work.

One suggestion, unscrew the spark plug and reconnect the high voltage wire. In a very dark area move the plug so that the plug thread touches some metal on the engine. Pull the starter cord. If you don't see a spark, remove the two screws on the handle and see if two wires are attached to the Stop Engine Switch. Remove one wire and bend it away from metal and try to see spark when pulling the start cord. If spark occurs, the Switch is shorted and needs replacing.