High Current Draw, 20Amp Fuse Blowing & Smoked LED Headlight

[CaptnDanLKW]

Troy Bilt Super Bronco (2005) - 13AX60TG766. Will have to

The carb has a solenoid but no backfire specific one i know of - a) both from having my hands in every area of the mower and b) if I dont throttle down and wait 2 seconds before shutting off, it backfires something fierce.

I JUST put a brand new regulator in. I mean it CANT be that, can it? I'm gonna test the voltage off the alternator next. Can a bad alternator burn out a bran new regulator?

Clarification - Normal 12V DC at the Lights = Battery voltage as measured at the battery (seems obvious statement but want to be sure)
While engine is running, battery voltage AT THE BATTERY (i.e. charging the battery) is less than 14.7... it was 14.2V-14.6V

The voltage at the headlight was 15.8V at full throttle.

Thanks again

 

[CaptnDanLKW]

If you have a an anti backfire solenoid when you disconnect the battery it may be shutting off the solenoid killing the engine. Have you tested the AC voltage output of the alternator? Have you replaced the battery? Bad battery can cause high current draw. When you say transformer are you refering to the alternator stator coil or the ignition coil?

Transformer = The part with the wire leading to the spark plug. So I’d say the ignition coil. I assume that is an isolated circuit just for to fire the spark plug.

Its a new battery from the beginning of the season.
Just to clarify, I had no electrical issues until I had this hard starting issue, which caused me to do a lot of cranking. (But always cautious not to over crank for too long). Starter motor is still nice and strong.
As I said in my other post, I’ll check the ac volts later today.

thanks again.

 

[StarTech]

Okay what the voltage output at the regulator during these tests as the voltage at the headlight should be the same as the battery. May have a faulty connection causing a large voltage drop between hte voltage regulator and the battery since it is lower than at the light.

 

[CaptnDanLKW]

Ok. Stumped other than the fact I received a new, bad rectifier-regulator, which still seems highly unlikely but not sure what else there is.

From the service manual..
1 Test - battery charging for no battery charge (skipped). There's definitely charge happening
2) Remove R-R connector, test voltage @ 3600RPM. Voltage ~38VAC at Idle, ~50VAC @3600. Good I Think. Specs say > 28VAC
3) Check stator resistance - 0.0 ohms - not open, good
4) Check each stator lead to ground - not shorted, good.

From the next section in the service manual - "test charging system for battery continuously charging at high rate"
Like @StarTech posted from the manual, Checking B+ to ground at 3600RPM I'm getting 15.8V, which is bad.

I traced all the wires and studied the wiring diagram. There are a number of safety switches and the obvious ignition switch (and backup PTO lockout override button) but nothing seems related. The B+ terminal feed back to the battery is quite simple and direct.

I guess I could leave the R-R disconnected and trickle charge the battery after each use, not sure how much battery draw there will be.

hmm.

 

[CaptnDanLKW]

Okay what the voltage output at the regulator during these tests as the voltage at the headlight should be the same as the battery. May have a faulty connection causing a large voltage drop between hte voltage regulator and the battery since it is lower than at the light.

Vout at B+ to ground is the same as the voltage at the headlights.

Vout at B+ to ground is NOT the same voltage as it is across the battery terminals (14.4ish vs 15.8) . (probably some load loss? / overcharging)

 

[CaptnDanLKW]

Closing out this post. It was the battery, though logically it shouldn't be since it cranks strong, has 12.2v without load and was trickle charged for days before installing. However i guess its a case of Occam's razor. I should have tried a different battery before heading down the rabbit hole.
I didn't put the old Rectifier-Regulator back in, but I suspect its fine.

Thanks everyone.