Aggravated!!!

JimG1967 · #1 05-06-2020, 08:31 AM

I’m from the proudly reopened state of Georgia and my grass gets taller by the day. I pastor a local church here, enjoy small engine mechanics, welding and the outdoors. Been married to my first wife for 29 years and have raised 3 kids who are all doing well.

I have a 2006 Cub Cadet zrt 50. The mower has been great. I am having a problem with the 20 amp fuse blowing after it cranks and runs for 10 to 15 seconds. This is what I have done so far:

1. Check the voltage coming from the coil/magneto 35 volts at WOT.
2. Changed the voltage regulator. $70.00
3. Checked the wiring diagram thoroughly.
4. Checked the voltage regulator for proper AC and DC output - good.
5. Put new aftermarket carburetor on cause I could not find a rebuild kit for the original.
6. Checked for any and all wire nicks, scrapes, or rub throughs.
6. New starter solenoid.
7. Checked my ignition switch for continuity several times - all good as far as I can tell. Also, took the ignition switch completely apart, cleaned, buffed, and shined all connections, regreased and reassembled.
8. Checked the PTO switch for continuity - all good.
9. Checked for continuity in wires (red/black) connected to the fuse holder.
10. Checked for nicked wires on PTO clutch under mower. (the fuse will blow without the PTO switch on)
11. Pull cover off to check for rubs or burn throughs on the afterfire solenoid on the carburetor - none.
12. Checked continuity on the afterfire solenoid- good.
13. Checked for ground on the carburetor solenoid - good.
14. Reconnected battery ground to mower frame.

Here is what i have found out so far. The motor will crank and run smooth with no problems until the B positive wire on the voltage regulator is plugged in. When it is plugged in with motor running, it will arc on the tab then it will arc on the jumper wire in the fuse holder. It will then slowly star too turn orange and smoke. If I unplug the B positive wire on the V regulator the fireworks stop. I have also noticed that the afterfire solenoid on the bottom of the carburetor will heat up just by turning on the switch. You can even hear it click if you wiggle the jumper wire in the fuse holder. You can also manually turn the cylindrical carburetor solenoid with your fingers, with with key 🔑 on, and feel and hear it open and close. I’m not sure if it is supposed to do this.

I do not know what else to do.

Any help would be greatly appreciated.

R Bedell · #2 05-06-2020, 08:55 AM

First, welcome to OCC.........

You say you have a 2006 RZT50. There is a Factory Code on the model/serial tag that helps fine tune the identity. In my research, that the RZT50 has two choices of engines, being Briggs and Stratton or Kawasaki.

Will have to have more information to further assist you.

Johnnysalami1957 · #3 05-06-2020, 09:40 AM

Quote:

Originally Posted by JimG1967

I’m from the proudly reopened state of Georgia and my grass gets taller by the day. I pastor a local church here, enjoy small engine mechanics, welding and the outdoors. Been married to my first wife for 29 years and have raised 3 kids who are all doing well.

I have a 2006 Cub Cadet zrt 50. The mower has been great. I am having a problem with the 20 amp fuse blowing after it cranks and runs for 10 to 15 seconds. This is what I have done so far:

1. Check the voltage coming from the coil/magneto 35 volts at WOT.
2. Changed the voltage regulator. $70.00
3. Checked the wiring diagram thoroughly.
4. Checked the voltage regulator for proper AC and DC output - good.
5. Put new aftermarket carburetor on cause I could not find a rebuild kit for the original.
6. Checked for any and all wire nicks, scrapes, or rub throughs.
6. New starter solenoid.
7. Checked my ignition switch for continuity several times - all good as far as I can tell. Also, took the ignition switch completely apart, cleaned, buffed, and shined all connections, regreased and reassembled.
8. Checked the PTO switch for continuity - all good.
9. Checked for continuity in wires (red/black) connected to the fuse holder.
10. Checked for nicked wires on PTO clutch under mower. (the fuse will blow without the PTO switch on)
11. Pull cover off to check for rubs or burn throughs on the afterfire solenoid on the carburetor - none.
12. Checked continuity on the afterfire solenoid- good.
13. Checked for ground on the carburetor solenoid - good.
14. Reconnected battery ground to mower frame.

Here is what i have found out so far. The motor will crank and run smooth with no problems until the B positive wire on the voltage regulator is plugged in. When it is plugged in with motor running, it will arc on the tab then it will arc on the jumper wire in the fuse holder. It will then slowly star too turn orange and smoke. If I unplug the B positive wire on the V regulator the fireworks stop. I have also noticed that the afterfire solenoid on the bottom of the carburetor will heat up just by turning on the switch. You can even hear it click if you wiggle the jumper wire in the fuse holder. You can also manually turn the cylindrical carburetor solenoid with your fingers, with with key 🔑 on, and feel and hear it open and close. I’m not sure if it is supposed to do this.

I do not know what else to do.

Any help would be greatly appreciated.

Check the ohms on whatever loads that are on the circuit. It sounds like there is a short internally on whatever is on that circuit. I would start connecting everything on that circuit one by one until you see the ohms drop to near zero. Put one ohmmeter lead on the downstream side of the 20 amp fuse connection. Ground the other lead and start re-connecting things.

JimG1967 · #4 05-07-2020, 06:57 PM

Thank you for the welcome Mr. Bedell. Yes, the model number would help.

Cub Cadet 735-735 17AA5 B7P756

Kawasaki FH661V-AS05 engine

JimG1967 · #5 05-07-2020, 07:04 PM

I forgot I had an actual picture of the tag under the seat.

Model Number 4429183 17AA5D7P709

Serial Number 1D186G90277

DOM 4/2006

These are the numbers from the actual sicker under the seat. The numbers I posted above ..... I'm not sure - I had them store on my phone from another place.

JimG1967 · #6 05-07-2020, 07:06 PM

The Engine is the Kawasaki FH661V-AS05

R Bedell · #7 05-08-2020, 08:06 AM

Quote:

until the B positive wire on the voltage regulator is plugged in. When it is plugged in with motor running, it will arc on the tab then it will arc on the jumper wire in the fuse holder. It will then slowly star too turn orange and smoke.

You have a short on the line (RED/BLK Wire). You will need to trace this down.
As an educated guess, it sounds like this wire is cut and grounding out.

cooperino · #8 05-08-2020, 08:18 AM

Quote:

Originally Posted by R Bedell

You have a short on the line (RED/BLK Wire). You will need to trace this down.
As an educated guess, it sounds like this wire is cut and grounding out.

Roland
Did not look at schematic, but couldn't this short be right in the key switch?

R Bedell · #9 05-08-2020, 08:21 AM

YES, the RED/BLK goes to the Ignition Switch. The short is in either the Input or Output to that circuit.

JimG1967 · #10 05-08-2020, 12:14 PM

Thank you again for the help and the diagnostics. I will have to retrace some steps I believe I have already taken. It could certainly be me, though I think I am thorough.

I have previously removed the switch and run the continuity tests on it according to the wiring diagram as shown below - it appeared to be fine - maybe I missed something.

OFF M + G
RUN B + R
START B + R + S

I have also run a separate ground from the voltage regulator to the negative side of the battery which did not change anything.

So the input of this circuit would be from the B+ on the voltage regulator?

The output would be the ignition switch?

One more thing, I did another test of the voltage coming of the B+ spade of the voltage regulator at WOT which measured 15+ volts DC. Is this an issue? I thought this voltage was supposed to be in the 14's. Just wondering.

Thanks again for your time and patience.