Z121S Floods and Stalls

wiredhot

New member

Equipment
Z121S, MX4700
May 16, 2020
4
1
0
Thomasville,GA
The other day, my mower stalled out after a few minutes of mowing. I removed the air filter the carburetor was full of fuel. I've gone through carburetor and all diaphragms are intact, no adjustments were made. I inspected and cleaned the fuel pump there was some dust and debris behind it. I disassembled and cleaned all the diaphragms and springs inside. And verified that it was working. No fouling on the plugs, and I don't run ethanol gas through ANY of my small engines. It can sit for a little while then it will start up and run like a top. After it warms up though it all goes to !@#$. My next step in my little pea brain is to pull the tank and verify that there is no debris in it. It is still giving me fits. I have checked all my lines and filters. Any other ideas? It is a Kohler 21 HP ZT 720. I bought the mower about 3 years ago and this is the 1st time I have had ANY problems with it. Thanks for the help.
 

mickeyd

Active member
Lifetime Member

Equipment
2014 L3200 DT w/LA524 FEL, 2019 Kubota Z121S w/ 48" Pro Dec, TG1860G w/RCK54TG
Mar 21, 2014
1,192
17
38
Guin, AL
Have you had all the recalls/campaigns performed on it?

I had a similar problem and the dealer performed the recalls/campaigns and now it run perfectly.
 
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BigG

Well-known member

Equipment
l2501, FEL, BB, Rotary cutter, rake,spreader, roller, etc. New Holland TL80 A
Sep 14, 2018
1,950
774
113
West Central,FL
Check the float in the carb and make sure that the it will float I have seen them develop holes that become filled with gasoline make them hang open and flood the engine. Second thing is to check the needle valve that is attached to the float for any damage. Also check the seat of that valve. Just a tiny spec of dirt will allow the fuel to flow into the carb and flood it.

The carb gasket kits are outrageously priced $72 at the dealer. I bought the cheap one off of fleabay for $8 and it has worked so far. Mine also had some bad o-rings that had to be replaced.

Good luck.
 

wiredhot

New member

Equipment
Z121S, MX4700
May 16, 2020
4
1
0
Thomasville,GA
I have not received any information from Kubota on any recalls affecting my mower. I did inspect the carb float and needle valve for any unusual wear. None was present and I cleaned all of the orifices inside the carburetor and blew them out with clean dry air. I started it today and it will idle perfectly but twill then bog down and I can pull the vent line from the fuel pump that connects to the exhaust manifold and it levels out. I reconnected it and it will bog back down. I had my son sit on it and start it up and when it does the governor will slam shut. I'm not any kind of small engine expert but is that normal?
 
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mickeyd

Active member
Lifetime Member

Equipment
2014 L3200 DT w/LA524 FEL, 2019 Kubota Z121S w/ 48" Pro Dec, TG1860G w/RCK54TG
Mar 21, 2014
1,192
17
38
Guin, AL
I have not received any information from Kubota on any recalls affecting my mower. I did inspect the carb float and needle valve for any unusual wear. None was present and I cleaned all of the orifices inside the carburetor and blew them out with clean dry air. I started it today and it will idle perfectly but twill then bog down and I can pull the vent line from the fuel pump that connects to the exhaust manifold and it levels out. I reconnected it and it will bog back down. I had my son sit on it and start it up and when it does the governor will slam shut. I'm not any kind of small engine expert but is that normal?
Kubota didn't notify me either but I found out on here. It won't hurt to call the dealer service dept. and see.
 

wiredhot

New member

Equipment
Z121S, MX4700
May 16, 2020
4
1
0
Thomasville,GA
Ok, first off, I seem to have repaired/ fixed the issue. I did check Kubota's site and there are no recalls for my particular mower. I verified that all my vent lines were clear, readjusted the throttle cable and the govenor per the Kohler manual located here. After that it seems to run fun and doesn't stall or flood. If you guys see anything that I did wrong or needs to be put back, please feel reef to let me know....
 

mickeyd

Active member
Lifetime Member

Equipment
2014 L3200 DT w/LA524 FEL, 2019 Kubota Z121S w/ 48" Pro Dec, TG1860G w/RCK54TG
Mar 21, 2014
1,192
17
38
Guin, AL
What is the serial number on your Z121s?

Here is a direct RECALL:
ZERO TURN MOWERS SAFETY NOTICE
KUBOTA RECALLS ZERO TURN MOWERS DUE TO FIRE HAZARD (RECALL ALERT)
RECALL SUMMARY:
NAME OF PRODUCT:
Kubota Zero Turn Mowers

HAZARD:
The throttle cable can make contact with internal electric wiring, posing a fire hazard.

REMEDY:
Repair
Consumers should immediately stop using the recalled Zero Turn Mowers and contact an authorized Kubota dealer to schedule a free inspection and repair. Kubota is contacting all known purchasers directly.

RECALL DETAILS:
UNITS:
About 3,850
DESCRIPTION:
This recall involves model years 2018 and 2019 Kubota ZD100 series gasoline-powered zero turn mowers. The model is printed on the side of the mowers. The data plate is located on the lower frame of the unit and contains the serial number and model number. Recalled units are orange and black.
Model: Serial Number Range:

Z122EBR-48
BEGIN 21408
END 2207

Z121SKH-48
BEGIN 31302
END 32882

Z125EBR-54
BEGIN 16242
END 16547

Z125SKH-54
BEGIN 29458
END 31138

There are several other Campaigns.
 
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