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Riding mower runs for about 20 mins then stops

#1

J

JP98

My Bad Boy MZ Magnum runs for about 20 mins then stops. It starts to sputter like it's running out of gas then quits. I have a full tank of gas in it. I'd let it sit for about 10 to 15 mins, start it again and the same thing happens. Runs for a bit then quits. Fuel pump? Fuel filter? Carb issue? Any suggestions where I should start? Thanks!
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#2

R

Rivets

Two things to check the next time it happens. As soon as you feel it starts to quit open the gas cap. If it continues to run, your gas cap is bad, vent plugged, and needs to be replaced. If this is not the problem, purchase an inline spark tester, and check for spark as soon as it quits. No spark coil has either a hot short or hot open and the coil needs to be replaced. Let us know what you find.


#3

J

JP98

Rivets said:
Two things to check the next time it happens. As soon as you feel it starts to quit open the gas cap. If it continues to run, your gas cap is bad, vent plugged, and needs to be replaced. If this is not the problem, purchase an inline spark tester, and check for spark as soon as it quits. No spark coil has either a hot short or hot open and the coil needs to be replaced. Let us know what you find.
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Awesome suggestion! I'll start with that gas cap. Easy enough to do. I did not realize gas caps go bad like that. If it is a bad gas cap, can I drill a tiny hole on it?
I'm going to go ahead and buy a spark tester online. It's cheap enough and I'll probably need it at some point anyway. Thanks for your suggestions.


#4

M

MParr

Does it have a Yamaha engine on it? If so, get rid of it.


#5

J

JP98

MParr said:
Does it have a Yamaha engine on it? If so, get rid of it.
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It's a Kohler 7000 series. Is this a good one?

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#6

M

MParr

JP98 said:
It's a Kohler 7000 series. Is this a good one?
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Better than the Yamaha.
Start looking for a fuel delivery problem.


#7

A

Auto Doc's

The next possibility is debris floating around in the fuel tank and blocking the fuel pickup tube. That or the fuel shutoff solenoid on the fuel bowl is getting hot and shutting off.


#8

J

JP98

Auto Doc's said:
The next possibility is debris floating around in the fuel tank and blocking the fuel pickup tube. That or the fuel shutoff solenoid on the fuel bowl is getting hot and shutting off.
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Thanks for your suggestion. I'm going to try the gas cap trick first. I'll add this as a possible cause if it's not the gas cap and/or the ignition coil.


#9

M

MParr

How old is this mower?
Fuel lines deteriorate with age. They might look good on the outside but can be flaking off on the inside. Trash inside of the tank can cause the described problem. It can float around until it blocks the pickup tube. The engine shuts down and the trash falls away from the pickup tube.


#10

J

JP98

MParr said:
How old is this mower?
Fuel lines deteriorate with age. They might look good on the outside but can be flaking off on the inside. Trash inside of the tank can cause the described problem. It can float around until it blocks the pickup tube. The engine shuts down and the trash falls away from the pickup tube.
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It was built in 2016, according to the serial number. I'm not the original owner so I do not know the maintenance history.


#11

J

JP98

Rivets said:
Two things to check the next time it happens. As soon as you feel it starts to quit open the gas cap. If it continues to run, your gas cap is bad, vent plugged, and needs to be replaced. If this is not the problem, purchase an inline spark tester, and check for spark as soon as it quits. No spark coil has either a hot short or hot open and the coil needs to be replaced. Let us know what you find.
Click to expand...
Ok, so it's not the gas cap. I tried to cut the lawn today and sure enough, 15 mins into it, it started to sputter. I immediately open the gas cap and it made no difference. It still quit. I got my inline spark tester and I got sparks. But maybe by the time I got my tester from my garage and walk back to my mower, it must have been about 5 mins. Maybe enough time for spark coil to cool down??

I'm going to order 2 new spark coils, spark plugs, a fuel filter, and a fuel pump. Easy enough to change the pump and filter so if those are the culprits, I'll return the spark coils. Amazon Prime cost me nothing to return them anyway.


#12

S

slomo

Other guys have good suggestions.

Normally when time comes into play, mower dies after 15 mins, trash in the fuel tank. Could be a weak ignition coil getting hot failing.
JP98 said:
It starts to sputter like it's running out of gas then quits.
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Sounds just as I and the others described.


#13

A

Auto Doc's

I believe the fuel tank pickup line is going to be the issue. They collect debris over time and it is very subtle for it to gradually choke up and restrict fuel flow. When the mower shuts down, the "stuff" relaxes then allows fuel flow for a short time until it acts up again.

There are a very few machines that have a screen on the end of the pickup tube, but sediment will even get through the screen eventually.

The strangest fuel restriction I have seen was a Cub Cadet Z-Force that actually had a 90 degree elbow with a worn plastic shutoff valve. Right at about 15 minutes of mowing time, I happened to look at the shutoff knob and it had partially moved to the closed position due to vibration. It was shutting off the fuel flow by itself.

The video that MParr sent you is a very real problem that even good shops miss. Anywhere there is and elbow or a valve in a fuel line is a potential for debris to collect. Grass clippings, bugs and even dust all collect in a fuel tank over years of use.

All fuel lines need to be blown clean with compressed air from time to time to minimize this problem.


#14

M

MParr

Auto Doc's said:
I believe the fuel tank pickup line is going to be the issue. They collect debris over time and it is very subtle for it to gradually choke up and restrict fuel flow. When the mower shuts down, the "stuff" relaxes then allows fuel flow for a short time until it acts up again.

There are a very few machines that have a screen on the end of the pickup tube, but sediment will even get through the screen eventually.

The strangest fuel restriction I have seen was a Cub Cadet Z-Force that actually had a 90 degree elbow with a worn plastic shutoff valve. Right at about 15 minutes of mowing time, I happened to look at the shutoff knob and it had partially moved to the closed position due to vibration. It was shutting off the fuel flow by itself.

The video that MParr sent you is a very real problem that even good shops miss. Anywhere there is and elbow or a valve in a fuel line is a potential for debris to collect. Grass clippings, bugs and even dust all collect in a fuel tank over years of use.

All fuel lines need to be blown clean with compressed air from time to time to minimize this problem.
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I'm leaning towards trash in the tank and deteriorating fuel lines.


#15

sgkent

sgkent

I just had a device that had been stored act that way. Blew out the lines and all was good. No idea what got into a sealed system but it did somehow.


#16

J

JP98

Thanks for all the input, fellas! I guess while I'm already changing the fuel filter and fuel pump, I might as well blow out the lines too.


#17

M

MParr

JP98 said:
Thanks for all the input, fellas! I guess while I'm already changing the fuel filter and fuel pump, I might as well blow out the lines too.
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You may want to remove the fuel tank and clean it out. It's better to get everything cleaned out than throw more parts at it.


#18

J

JP98

MParr said:
You may want to remove the fuel tank and clean it out. It's better to get everything cleaned out than throw more parts at it.
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I was trying to avoid doing that, but I know I really should do it. I looked inside the fuel tank, and it looked clean. I know.... I'm just being lazy. I really need to do it.
The fuel pump and filter are pretty cheap so I figured I should go ahead and do that as well. I have a spare shut off valve. Might as well install that too since it doesn't have one.


#19

M

mcspeed

I would start by blowing out fuel line. If this fixes it you know what the problem was. Throwing multiple parts at leaves you hanging with what the actual problem was……assuming it actually fixes the problem.


#20

S

Silviasil

Auto Doc's said:
The next possibility is debris floating around in the fuel tank and blocking the fuel pickup tube. That or the fuel shutoff solenoid on the fuel bowl is getting hot and shutting off.
Click to expand...
My vote is the latter. I would highly suspect a weak fuel shutoff solenoid. I had the same symptoms last year and found real fine “grit” down around the spring of the plunger. I cleaned it up and it worked for a year. However this year same symptoms and found the body of solenoid getting hot. Took a short pice of toothpick jammed in beside the plunger (to keep the plunger retracted) reinstalled and after using mower 3 times did not have the problem. Replaced the solenoid (it stays cooler) and engine runs normally.


#21

R

Rebel1

If you haven’t already changed the fuel filter, I’ve seen a semi plugged filter cause that same problem.


#22

A

ajwgator

My Gravely Z260 did the same thing. It would only run 15 minutes and die. It was the fuel filter causing it. Chased it for a week thinking it was a week fuel pump but in the end the filter cleared it up.


#23

R

RevB

MParr said:
Does it have a Yamaha engine on it? If so, get rid of it.
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Engine Options: Kawasaki, Kohler & Briggs...never offered with a Yamaha.


#24

R

RevB

JP98 said:
Ok, so it's not the gas cap. I tried to cut the lawn today and sure enough, 15 mins into it, it started to sputter. I immediately open the gas cap and it made no difference. It still quit. I got my inline spark tester and I got sparks. But maybe by the time I got my tester from my garage and walk back to my mower, it must have been about 5 mins. Maybe enough time for spark coil to cool down??

I'm going to order 2 new spark coils, spark plugs, a fuel filter, and a fuel pump. Easy enough to change the pump and filter so if those are the culprits, I'll return the spark coils. Amazon Prime cost me nothing to return them anyway.
Click to expand...
Like being a parts cannon, eh? Isolate then buy. Don't just throw crap at it till you know what it is....


#25

J

JP98

RevB said:
Like being a parts cannon, eh? Isolate then buy. Don't just throw crap at it till you know what it is....
Click to expand...
I'll order the parts that I might need and use the one I need. What's wrong with having them ready on standby??
Return the other ones. Amazon Prime benefit.


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