Question-------------------------
Allen,
Thanks for that fast reply! This is a Murray 38701c. The Tecumseh is TEC12 which lead me to believe it was a 12HP. It has 2 numbers on the sticker if those will help. I was able to find a wiring diagram after googleing the Murray number. Now Im just getting weak spark. Im pretty sure I dont have a points system, I know what those look like. I do have 3 wires in the ignition system. 2 going up to what I thought was the magneto(AC & DC source) according to the diagram. And one to the coil. Im about to try to replace the coil because of the weak spark. Let me know what you think.
Thanks again,
Kevin
Followup To
Question -
Hi ,
Im an auto mechainc working on a riding mower....sigh.
This was given to me with the wiring all torn up.
My problem at this point is no fire for the Tecumseh12. I can get it to turn over, but havent worked with this type of ignition system. I've had to bypass the seat switch and other safety switch.
I have 2 wires (black & white) going from the key to the magneto. and a green wire from the key to the coil.Just dont know what they should be reading. Im basically looking for a wiring diagram, but some pointers would be much appreciated! thanks!
Answer -
Hiya Kevin- OK- a little confusing, you say you have a 12hp Tecumseh with a battery, coil, electric start AND a magneto? -Reason I ask is that these are two different ignition systems altogether. Magneto's are for small engines without a 12v system. I'll assume for the moment you DON't have a magneto, but a battery-generator-starter-coil setup.
Since you have it "cranking", we'll pass the starter circuit as ok.
-On the ignition side, there will be a terminal from your key switch that is hot anytime the key is not in the off position. The wire from this terminal goes to your coil + TERMINAL (note- pay attention to the wires, SOME 12v mowers use a ballast resistor in the hot lead to the coil. Miss this, and you'll burn out your coil, look for a wire with a thick section- if unsure, hook it up and feel the coil fairly often, it should not get too hot to touch). The negatiive coil post should go to your points (the condenser if point pad is on the condenser, the condenser AND one of the point arms if they are seperate. The other point arm will go to chassis ground)
Verify +12v to your coil (+) terminal, on the (-) terminal, it should go +12v to 0, back and forth as the engine rotates and the points open and close.
If this much is ok- do a spark test, clamp the plug to a fin and attach spark lead- crank over engine (tip- use a new plug) If no spark- your hi tension lead from the coil to the plug is bad.
Lemme know how it goes- & if we need to go further give me the model number off the engine or mower
AnswerHi again Kevin
Listen - be sure about this, when you say "weak spark" make sure you're talking about an inconsistant or very intermittant spark across the plug gap. Don't depend on the color for gaging the strength of a spark. Do a gap test before you change the coil-
lemme know!
