15.5hp Tecumseh on Yard Machines will not charge battery. Wires are good?

The charging system on most small engines is by magneto system. The flywheel has magnet in the edge which induces current to flow in a coil (pick-up)mounted very near. The coil has one side connected to ground and the other to the battery. The mowers headlights by the way are powered directly from the magneto. That is why they only work if the engine is running.

Make sure wires are not disconnected from pick-up coil to battery. Note: Probably will only have one wire as the frame serves as ground. Also the wire probably won't go directly back to battery, but to a common point like the starter solenoid or key switch.

As for hard starting, probably not battery or starter if mower is old, exhaust valve clearance (lash) too slack. Causes compression not to be released quick enough because the cam moves but the valve does not open immediately and the starter can not overcome the compression on big one cylinder piston engine. See You Tube 14.5 hp B&S hard to start/ valve adjustment.

Leonard Bonamo
August 2013

Yard Machines tractor lawn mower w/ 15.5 hp Tecumseh engine. Model - 13A6673G118, Engine Model OHV155 - 204509E - It was a bad starter solenoid relay - I purchased one (in stock) at my local hardware store. I installed it and now it starts every time. This must be a common problem with these. The True Value had the solenoid relays in stock. They said they sell them fairly often. The MTD p/n for the starter solenoid relay is 925-1426A and on the STENS box it says part # 435-431. Thanks for the good website. :>)

Stanley
August 2010

I have the same Tecumseh Yard Machines 15.5 HP / 42" deck- the starter solenoid seems to be the problem - I have hit it and made the starter motor engage okay.
As reported above, then it starts fine and runs well. Until I shut it off. Then, it is a 50/50 chance the starter motor will engage and not just click click the starter solenoid. I am still trying to get the Yard Machines part.

Stanley
August 2010

I have the same problem. I charged the battery and it acts as though the battery does not have enough charge. I have gone and got a bigger amprages size battery and it still does the same thing. The starter is dragging. Could this be a bad starter or a starter that is to small for this size engine?

Bob
May 2008