Question about Husqvarna Zero Turn Mower Z5426

1 Answer

Husqvarna z5426 running rich and fouling plugs

My mower starts fine but after running for a few minutes, it seems as though something in the carbs isn't working properly and too much gas is being pumped in. I took out the plugs and noticed that one plug had been fouled up and I had just replaced them. When it starts to run rich it bogs down and tries to cut off.

Posted by on

  • ransome1200 Jun 01, 2009

    Thanks Captain! I'm going to tackle it tomorrow.



1 Answer

  • Level 1:

    An expert who has achieved level 1.


    An expert whose answer got voted for 20 times.


    An expert that has over 10 points.


    An expert whose answer got voted for 2 times.

  • Contributor
  • 15 Answers

Sounds like a fouled needle seat, or the float bowl is failing.

Start with:

Pulling your Carb, and cleaning it out. COMPLETELY.
A ton of people think "a shot of carb cleaner, and a gasket kit" is a carb fix. It is NOT, and WILL NOT fix a carb, if the problem isn't gaskets, and shots of cleaner!

Meaning, if she is running too rich, then too much fuel (as you said), and fouling plugs, remember there are only a VERY few things in the carb anyway as it is.

1. Needle Seat
2. Fuel Float Bowl
3. Butterflies
4. Fuel Ports
5. Air Ports
6. Gaskets/Diaphragms.


Pull the carb (Carefully!) and tear it COMPLETELY down (Carefully!). Note where stuff went, take your time, be patient.

When you have everything but the butterfly plates out, run some Gum-Out through each and every port, after you made sure to pull the Float Bowl, and the Needle Valve (and remembered how they went back in there!). Take some compressed air, and follow through (CAREFULLY!) on each and every port. Clean the very TIP of the Needle Valve. Shake your plastic Float Bowl. Does it have liquid inside? She has a hole in her. REPLACE!

If not, then this exercise was cleaning crud/residue that is ALWAYS building up inside carbs in 2/4-stroke engines world wide, every day. NOW do a "carb gasket rebuild".

Note: Remember that sometimes, crud/junk is testy, and stubborn as a mule to get out. Double check any screens above/below your Needle Seat and Valve. Remember that Needle Valves come with solid tips, and some with rubber tips. Regardless, be careful, and clean thoroughly! A Needle Seat that isn't getting closed, is a Needle Valve that is letting WAY too much fuel in!

Posted on May 30, 2009

  • Captain Slap Jun 02, 2009

    Not a problem! I hope to hear back from you that you fixed 'er up!

    If not, I am sure we can whoop it! (Patience and Lawnmowers......they go hand in hand!)



1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017


Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

Carbon fouling spark plugs

Weak Spark, worn piston rings(Burning oil/compression issues), lack of compression, wrong spark plugs, incorrect spark plug gap, engine not reaching operating temperature (Due to short use), carb. is running rich (May need adjusting), dirty air filter (Causing carb. to choke and run rich). Bad gas
All these symptoms could lead up to fouling plugs.
Hope This Helps.

Sep 27, 2013 | Garden

1 Answer

What number of spark plug do I use for z5426

Sparkplugs/Gap: Champion RC12YC .030"/0.75mm

You can download the owners manual free of charge from their site:

Apr 10, 2012 | Husqvarna Zero Turn Mower Z5426

1 Answer

My wife put diesel fuel in the gas tank trying to help me. I have drained all the fuel put new fuel filter on and it still will not start. I think there must be diesel in the carburetor bowl. Is it...

squirt some gas in the carb and start it up it will only run for a few secs so quickly keep squirting gas in ,but not to much as to flood it and that should burn the diesel out and shortly it should keep running

Jul 25, 2011 | Husqvarna Zero Turn Mower Z5426

1 Answer

A friend cleaned the filters and changed plugs when it started putting out back smoke. Shortly thereafter it starting losing power and put out more black smoke . He said the deck was dragging and the pugs...

Thanks for choosing FixYa and welcome. Since you are seeing smoke, it is usually a sign for rich gas and air mix. This could be caused by a choke that is slightly closed, a defective carburetor, or the carb may just need adjusted. You need to make sure the choke is completely open though. I would suggest cleaning the carb and adjusting it if necessary. Refer to your manual for the correct procedure. Check around your cylinder, head, and the shroud of the mower. Make sure the cylinder has nothing on it to cause smoking. See if cleaning the carb helps the performance. You may need to change the plug wires, if you didn't the first time. You could have a bad plug wire. Sometimes you get bad plugs but it is very rare to do so.

May 24, 2011 | Husqvarna Riding Lawn Mower Yth24v48ls 48...

2 Answers

My Troy Bilt self propelled lawn mower keeps fouling spark plug out after one use. Why?

Hi , it can often be something as simple as the engine needing a oil change as oil looses viscosity/thins with use ( use correct grade ), replace or clean the oil filter and a good service or something more complex which requires a full engine stripdown like worn piston ring/oil scraper ring causing oil to flow up the cylinder walls and fouling the combustion chamber or oil leaking up through the valve stem oil seals , also storing the machine tilted can cause oil to collect in the chamber or petrol to leak into the sump causing the oil to thin.
Hope this helps , please rate accordingly

Aug 31, 2010 | Troy Bilt 5.5hp Self Propelled Mower

1 Answer

Husqvarna Z6127 won't start after running 30 minutes.

If the starter motor is spinning, the problem is probably the starter motor solenoid. It is basicly an electric piston mounted on the starter that engages the starter motor pinion gear to the flywheel.

Jul 31, 2009 | Husqvarna Zero Turn Mower Z5426

1 Answer

John deere js60 lawnmower is fouling the spark plug in 20 minutes. gas is good other mower works fine with same gas. can not locate fuel filter if it has one. large deposit of smut on plug.

sounds like your carb. is running rich for some reason
be sure to check to be sure your choke is fully off when running
follow your fuel lines they may have stuck the filter somewhere or they may be only using a tank screen filter.
Be sure you have the proper plug installed and gapped .030
most common plugs that are used the most is J19LM or RC12 YC

couple things to check for you mowers issue

Jun 11, 2009 | Toro Lawn Mower With Toro Power Tools

Not finding what you are looking for?
Husqvarna Zero Turn Mower Z5426 Logo

544 people viewed this question

Ask a Question

Usually answered in minutes!

Top Husqvarna Garden Experts

Phil Walker
Phil Walker

Level 3 Expert

608 Answers

Doctor PC
Doctor PC

Level 3 Expert

7733 Answers

Roland W VanLue
Roland W VanLue

Level 3 Expert

486 Answers

Are you a Husqvarna Garden Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides