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M-ZT 52 Stops running when hot!

#1

L

littlegman

I have a Husqvarna M-ZT52 with the Kawasaki FS651V motor. I have had it about 5 years and has served me well, about a month ago while mowing my 2 acre lot, it would quit running about 1/2 way threw and would not start until it sat there about an hour. It looked like the fuel filter was empty so I figured the fuel pump was going. so I installed new fuel pump and filter but is still doing the same thing. I know its hot here in Tennessee but no different than other year but never had this problem before, any suggestions ?


#2

S

slomo

Pull fuel line off AT carb inlet. See what you get when cranking the engine.

Even better, crank/pump into a glass jar and look for water.

Most likely fuel tank is plugged with grass, bugs, dirt dobbers and leaves. Tank output knecks down and trash plugs this up. Dead tank cap gasket adding to the mix.


#3

L

littlegman

slomo said:
Pull fuel line off AT carb inlet. See what you get when cranking the engine.

Even better, crank/pump into a glass jar and look for water.

Most likely fuel tank is plugged with grass, bugs, dirt dobbers and leaves. Tank output knecks down and trash plugs this up. Dead tank cap gasket adding to the mix.
Click to expand...
Thanks for the suggestions, I will definately check them out.


#4

R

Rivets

Get yourself an inline spark tester and the next time it happens install the tester and check for spark. I suspect you will find no spark. You have either a hot short ot hot open, which means the coil will need to be replaced.


#5

S

slomo

Taryl made a video explaining the coil tester types. He said and I agree, the light bulb type does not give the full picture of coil performance. Taryl said to get the Briggs type or even better the PET-4000. He had a coil that would fire at low revs then crap out at mid and high revs. I've seen the same thing several times. Reason why I bought a PET-4000.
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#6

R

Rivets

I see I no need for the average DIY guy to purchase one of the expensive testers, which he will use as once or twice. I’ve used the simple neon tester for ever and have not had any problems. Do have one in my box, but I would be lying if i told you the last time I used it.


#7

A

Auto Doc's

For both coils to fail at the same time is highly unlikely. Usually, a reduction in power is quickly noticed, but not a total shutdown.

I would study the fuel system closer. Trash in the tank getting sucked into the pickup tube is fairly common. Bugs, dirt and grass clippings get into fuel cans easier than people realize.

A common issue I run across at about this age is the fuel pump pulse line getting cracks in it. When that happens the fuel pump quits working because the line gets hot and swells just enough so the crankcase pulses will not operate the fuel pump.

A spark tester is nice but use only the ones you can adjust the air gap on by hand. Ebay has them for just a few bucks each. Do not get the one with the bulb in them, they are unreliable.

The other item to check is the main power fuse to make sure it is not getting hot or fitting in the fuse holder loose.

The next item to check is under the upper engine cover. Mice love to nest up inside them and grass clipping along with dirt collect and choke down the cooling air fins.

Hope this helps you.


#8

A

Auto Doc's

For both coils to fail at the same time is highly unlikely. Usually, a reduction in power is quickly noticed, but not a total shutdown.

I would study the fuel system closer. Trash in the tank getting sucked into the pickup tube is fairly common. Bugs, dirt and grass clippings get into fuel cans easier than people realize.

A common issue I run across at about this age is the fuel pump pulse line getting cracks in it. When that happens the fuel pump quits working because the line gets hot and swells just enough so the crankcase pulses will not operate the fuel pump.

A spark tester is nice but use only the ones you can adjust the air gap on by hand. Ebay has them for just a few bucks each. Do not get the one with the bulb in them, they are unreliable.

The other item to check is the main power fuse to make sure it is not getting hot or fitting in the fuse holder loose.

The next item to check is under the upper engine cover. Mice love to nest up inside them and grass clipping along with dirt collect and choke down the cooling air fins.

Hope this helps you.


#9

S

slomo

This is Taryl's video where he talks about coil testers. I've seen this on about five or six coils. This is why I preach about the wide gap types as the superior tool.

Fast forward to 4:08 and ends at 7:03.



#10

Tiger Small Engine

Tiger Small Engine

Auto Doc's said:
For both coils to fail at the same time is highly unlikely. Usually, a reduction in power is quickly noticed, but not a total shutdown.

I would study the fuel system closer. Trash in the tank getting sucked into the pickup tube is fairly common. Bugs, dirt and grass clippings get into fuel cans easier than people realize.

A common issue I run across at about this age is the fuel pump pulse line getting cracks in it. When that happens the fuel pump quits working because the line gets hot and swells just enough so the crankcase pulses will not operate the fuel pump.

A spark tester is nice but use only the ones you can adjust the air gap on by hand. Ebay has them for just a few bucks each. Do not get the one with the bulb in them, they are unreliable.

The other item to check is the main power fuse to make sure it is not getting hot or fitting in the fuse holder loose.

The next item to check is under the upper engine cover. Mice love to nest up inside them and grass clipping along with dirt collect and choke down the cooling air fins.

Hope this helps you.
Click to expand...
Does the engine die suddenly like you turned the key off (electrical), or kind of chug a bit and come to a halt (fuel)?


#11

L

littlegman

slomo said:
Taryl made a video explaining the coil tester types. He said and I agree, the light bulb type does not give the full picture of coil performance. Taryl said to get the Briggs type or even better the PET-4000. He had a coil that would fire at low revs then crap out at mid and high revs. I've seen the same thing several times. Reason why I bought a PET-4000.
View attachment 71282
View attachment 71283
Click to expand...

Tiger Small Engine said:
Does the engine die suddenly like you turned the key off (electrical), or kind of chug a bit and come to a halt (fuel)?
Click to expand...
Thank you for all the tips. Mine kind of chugs a bit before coming to a halt, I believe it has to be the fuel because it will try to start with the choke on but will die out. After about 20 minutes or so, it will start again like there is no problem. I did change the fuel pump and filter but didn't seem to help. I replaced the fuel pump with a chinesee one off amazon and after I read to get that sometimes they are defective also. I do have a inline spark plug tester similar to the one in the other reply.


#12

L

littlegman

slomo said:
Pull fuel line off AT carb inlet. See what you get when cranking the engine.

Even better, crank/pump into a glass jar and look for water.

Most likely fuel tank is plugged with grass, bugs, dirt dobbers and leaves. Tank output knecks down and trash plugs this up. Dead tank cap gasket adding to the mix.
Click to expand...
yes and everything is clean under the shrouds


#13

L

littlegman

Rivets said:
Get yourself an inline spark tester and the next time it happens install the tester and check for spark. I suspect you will find no spark. You have either a hot short ot hot open, which means the coil will need to be replaced.
Click to expand...
thanks, I have a inline tester that I will try


#14

A

Auto Doc's

This has me leaning towards a coil breaking down when hot. The spray bottle shooting a stream of water on the exhaust pipe works well. If the water immediately burns off, the cylinder is producing power. If the water is slow to burn off, that is a cylinder not producing power.

Firmly bolted V-twin engines do not rock or give an obvious indication when one cylinder drops out, it just loses power and will stall, especially if the deck is engaged.

The second suspect is there is a floating chunk of debris or a dead bug that is intermittently blocking the fuel line spigot/ pickup in the fuel tank.


#15

M

mikewdan

littlegman said:
I have a Husqvarna M-ZT52 with the Kawasaki FS651V motor. I have had it about 5 years and has served me well, about a month ago while mowing my 2 acre lot, it would quit running about 1/2 way threw and would not start until it sat there about an hour. It looked like the fuel filter was empty so I figured the fuel pump was going. so I installed new fuel pump and filter but is still doing the same thing. I know its hot here in Tennessee but no different than other year but never had this problem before, any suggestions ?
Click to expand...
May sound a little silly but if none of the other ideas have not worked for you, check gas cap to make sure it is vented properly. I had this same thing keep happening to me and found that simple thing to be the problem.


#16

W

Wrenchit

littlegman said:
I have a Husqvarna M-ZT52 with the Kawasaki FS651V motor. I have had it about 5 years and has served me well, about a month ago while mowing my 2 acre lot, it would quit running about 1/2 way threw and would not start until it sat there about an hour. It looked like the fuel filter was empty so I figured the fuel pump was going. so I installed new fuel pump and filter but is still doing the same thing. I know its hot here in Tennessee but no different than other year but never had this problem before, any suggestions ?
Click to expand...
The gas cap vent stopped up. It's rare, but I have seen it happen a few times.
Also, when it quits, pull the plug wire and check for spark. Filing coil/s will shut an engine down until they cool off and start again. Then quit when hot.
Most fuel filters are rarely full when running, some look like there is not enough fuel to run, but they will.


#17

T

toolboxhero

littlegman said:
I have a Husqvarna M-ZT52 with the Kawasaki FS651V motor. I have had it about 5 years and has served me well, about a month ago while mowing my 2 acre lot, it would quit running about 1/2 way threw and would not start until it sat there about an hour. It looked like the fuel filter was empty so I figured the fuel pump was going. so I installed new fuel pump and filter but is still doing the same thing. I know its hot here in Tennessee but no different than other year but never had this problem before, any suggestions ?
Click to expand...
I haven't heard of this problem on a Husqvarna but it fairly common on the Cub Cadet lawn tractors.
The vent on the fuel cap may be plugged. It makes sense in your situation because the fuel filter is empty.
Open the fuel cap 1/4 to 1/2 turn and see if the problem goes away. If it does get a new cap.


#18

B

bentrim

When it shuts down have you checked the antifire solenoid (if it has one) in the carburetor bowl? Sometimes when they get hot they will not work properly and close. May have to check for a missing heat shield or fabricate one.


#19

B

Back44L&G

Rivets said:
Get yourself an inline spark tester and the next time it happens install the tester and check for spark. I suspect you will find no spark. You have either a hot short ot hot open, which means the coil will need to be replaced.
Click to expand...
I just went through that last week. I cleaned the carburetor, emptied and cleaned the tank. I removed the ignition module and cleaned the armature and checked the gap at ten thousands. The mower ran longer but spark diminished over time shutting down the engine. Then I purchased a replacement ignition module (coil) that corrected the problem. No further issues.


#20

G

Gord Baker

littlegman said:
I have a Husqvarna M-ZT52 with the Kawasaki FS651V motor. I have had it about 5 years and has served me well, about a month ago while mowing my 2 acre lot, it would quit running about 1/2 way threw and would not start until it sat there about an hour. It looked like the fuel filter was empty so I figured the fuel pump was going. so I installed new fuel pump and filter but is still doing the same thing. I know its hot here in Tennessee but no different than other year but never had this problem before, any suggestions ?
Click to expand...
Remove Fuel tank Cap and fuel line at filter. Blow back the line carefully with minimum pressure. Do this outside, off the driveway and don't be looking in the tank while you do it. Then blow the other direction using low pressure. If fuel flows OK, continue to removing Float bowl and be sure fuel flows with float raised. Remove carb jets and emulsion tube and clean all tiny orifices carefully. Rinse with Brake cleaner. Use eye protection.


#21

B

biggertv

Sounds like Coil going bad. Insulation breaking down with Heat. It's happened to me a couple of times with Briggs engines, they would last about 1/2 hour before quitting. New coil is the fix.


#22

Smithsonite

Smithsonite

I'm betting on a fuel cap vent with asthma.


#23

L

littlegman

Gord Baker said:
Remove Fuel tank Cap and fuel line at filter. Blow back the line carefully with minimum pressure. Do this outside, off the driveway and don't be looking in the tank while you do it. Then blow the other direction using low pressure. If fuel flows OK, continue to removing Float bowl and be sure fuel flows with float raised. Remove carb jets and emulsion tube and clean all tiny orifices carefully. Rinse with Brake cleaner. Use eye protection.
Click to expand...
So here is what I have done so far, I installed a new (second one) fuel pump, this time a Mikuni and took off the chinese knock off as I read sometimes these are just not reliable, new Kawasaki fuel filter, pulled the fuel line out of the tank and it was clean, new air filter, checked for grass under the engine shroud. I started it up and I had a much stronger flow of gas out of the hose at the carb. I figured I got it fixed, WRONG, about 3/4 my lawn done and it sputtered out and quit running. I let it sit about 15 minutes, it started and ran good again to finish my lawn. I am going to put new plugs in it this week and if that don't fix it, maybe one or both coils may get weak when they get hot? Its really got me scratching my head! About 250 hours on it and it ran like a beast and now letting me down...


#24

A

Auto Doc's

It sounds like you possibly have a blob of foreign contamination floating around in the tank and it is blocking the fuel pick up line at random. Old fuel cans are the worst for contamination buildup and possibly bugs getting in them.

Also, from what I can tell in a part diagram on Parts tree there is a vent check valve in the top of the tank for vapor emissions control. The valve may have failed and is creating a fuel cavitation (vacuum) in the tank. Try running until it acts up and then loosen the fuel cap and see if you can hear air sucking in as you loosen the cap.

Another possibility is if this has a special shaped pickup tube that is shaped to fit into the tank contour a certain way, it may be out of position and not picking up fuel when the fuel gets lower.

A couple of weeks ago, I had a John Deere 757 with a special shaped fuel tank tube that fit through the tank line grommet. It had to be "clocked" in the correct direction to work properly.


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