T1400 - Loosing Spark

[fredbear241]

It starts & stops when it feels like it :-(
Until this w/e it's been perfect. It stopped on a steep slope, after 4hrs running...I suspect possibly due to low oil. Extra oil got it running for a while (10mins)& it stoppped again. No spark. I changed oil & huge spark across plug returned & it ran again (20mins).
I move PTO lever & it stalled. 20mins later it started again...This is now ongoing, starts when it feels like it, and stops when it feels like it also. When 'stopped' there is no spark at plug, but if I remove plug cap & test HT lead there is a very faint spark from end of HT. I've cleaned all elec connections I can find. I've tried bypassing all the seat / pto / brake cutouts....no luck so far.

Q1. Does the 1400 have an oil pressure/low/high/quality sensor/switch?
Q2. How do I test / check the relay box? Can it be bypassed?
Q3. Could it be voltage reg, how do I test this?
Q4. Anyone have a wiring diagram?
Q5. What does the yellow wire to carb solenoid do? Can I bypass this as a test?
Q6. Is there some other sensor that cuts the spark

many thanks in advance for any clues / info to solve this.

 

[Chillidog]

Q1. No, it does not.
Q5. The yellow wire opens the fuel cutoff solenoid allowing fuel to enter the carb when the ignition is switched to 'on'. (Aside: This is an 'anti-dieseling' function and also prevents your engine from filling with gas during storage if the needle valve ever got stuck open -- can happen with gravity-fed fuel systems)
Q6. The seat switch and ignition switch cut spark. That's it.

First of all, oil pressure/fill level has nothing to do with your problem. The problem is likely caused by a faulty igniter that is not delivering sufficient spark. Typically they crap out when they get warm, but it can gradually progress. You probably weren't losing spark, just getting a weak spark when the engine stalled. That caused the loss of power.

If you want to do a simple spark strength test, take a good plug, expand the gap to perhaps double recommended, and with the plug grounded to the engine body, see if you get spark. The wider the gap it can jump, the stronger your spark. Test it when the engine is cold. Then, do the same test after it is nice and warm or after it stalls. A typical spark testing tool with lamp is no substitute. The lamp can light up even if the spark is weak.

You'll find the igniter by following your plug wire. It's under the engine's top cowling.

Hope it helps!