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I bought a used Cub Cadet CC30H, it starts and runs well for about 20 minutes, then it misfires and dies. I have fresh fuel, new fuel & air filter, new spark plug and oil/filter change.
After about 10 minutes it starts and does the same again. I don't hear a hiss after it dies and I loosen the fuel cap so doubt that's plugged. When I replaced the fuel filter I did install a paper element filter vs a red screen type, could that be a cause.

Yorston Bill said:

I bought a used Cub Cadet CC30H, it starts and runs well for about 20 minutes, then it misfires and dies. I have fresh fuel, new fuel & air filter, new spark plug and oil/filter change.
After about 10 minutes it starts and does the same again. I don't hear a hiss after it dies and I loosen the fuel cap so doubt that's plugged. When I replaced the fuel filter I did install a paper element filter vs a red screen type, could that be a cause.

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Is it a gravity fed fuel tank? Does it have a fuel pump? Did it have a red fuel filter on it initially?

How did it run before you changed those parts? If it is a 10 Micron filter it can cause the engine to starve for fuel since the engine does not have a fuel pump.

hlw49 said:

How did it run before you changed those parts? If it is a 10 Micron filter it can cause the engine to starve for fuel since the engine does not have a fuel pump.

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Tks for the reply, unfortunately I bought it at an auction, did the cleanup & tune up routine first, then noticed the issue with first use. I'll pick up a little red one and switch out the filter.

Tiger Small Engine said:

Is it a gravity fed fuel tank? Does it have a fuel pump? Did it have a red fuel filter on it initially?

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Tks for the reply, yes it had a red filter which I replaced, I don't think it has a fuel pump, hose from tank to carb.

Next time it happens check for spark. No spark means you have a coil which either opens or shorts when it gets hot. Time to replace coil.

According to the IPL this engine came the 70 micron White pancake filter per the PN. Now the Red pancake is a 150 micron filter. Many paper type are in the 25-30 micron range. Depending if the tank bottom is above the engine's top then these 25 micron filter usually still wok fine. I run a Briggs 33 series that is gravity fed without any problems using a 27 micron filter.

She how she runs with a straight raw fuel line off the tank. Or auxiliary fuel tank.

Do a visual inspection on the inside of the gas tank and make sure you don't have some debris that is floating around and then plugging the inlet hole (not making it to the filter). Floating again, and replugging.

StarTech said:

According to the IPL this engine came the 70 micron White pancake filter per the PN. Now the Red pancake is a 150 micron filter. Many paper type are in the 25-30 micron range. Depending if the tank bottom is above the engine's top then these 25 micron filter usually still wok fine. I run a Briggs 33 series that is gravity fed without any problems using a 27 micron filter.

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Tks for the reply, maybe not the problem

StarTech said:

According to the IPL this engine came the 70 micron White pancake filter per the PN. Now the Red pancake is a 150 micron filter. Many paper type are in the 25-30 micron range. Depending if the tank bottom is above the engine's top then these 25 micron filter usually still wok fine. I run a Briggs 33 series that is gravity fed without any problems using a 27 micron filter.

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I saw it both ways, red & white on youtube so taking a chance on red, if that fixes it I will try the white next time.

Rivets said:

Next time it happens check for spark. No spark means you have a coil which either opens or shorts when it gets hot. Time to replace coil.

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Tks for the reply, I am hoping that's not the issue, after it dies it fires a bit by key, seems like fuel starvation but sure could be spark week or inconsistent.

Tiger Small Engine said:

Is it a gravity fed fuel tank? Does it have a fuel pump? Did it have a red fuel filter on it initially?

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Had a red one when I bought it just couldn't find one locally.

Sounds to me the coil or the plug is failing when hot. Put the correct plug in it and see if it works like it should. If it fails again immediately check for no spark while it is hot. If no spark, the coil is suspect.

On a side note, make sure you oil is clean and full.

Last but not least is possible debris in the fuel tank. The tank is hidden rather well on these, and there is no telling what has collected over time by refueling with grass clipping all around or possible prior owner had a dirty fuel can. Debris floats around and will starve the engine for fuel.

Auto Doc's said:

Sounds to me the coil or the plug is failing when hot. Put the correct plug in it and see if it works like it should. If it fails again immediately check for no spark while it is hot. If no spark, the coil is suspect.

On a side note, make sure you oil is clean and full.

Last but not least is possible debris in the fuel tank. The tank is hidden rather well on these, and there is no telling what has collected over time by refueling with grass clipping all around or possible prior owner had a dirty fuel can. Debris floats around and will starve the engine for fuel.

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Will do, thanks for the advice. I haven't changed the filter yet, undergoing chemo so got good and not so good days.

I had similar issue on a different mower. Would run reliably for 45 min to an hour then die on me. I thought it was overheating or heat was causing an ignition issue. I changed filters, ignition coils, spark plugs and fuel pump with no effect.

Someone suggested debris in the fuel tank and that was the cause. The debris was too big to go down the fuel line and was blocking the outlet of the tank. This was a ride on mower used on quite rough ground so the fuel got sloshed about a lot, yet somehow after 45 min to an hour it blocked the outlet repeatably. If I left the mower overnight it would then run reliably again. How on earth it could run for so long and then die repeatable I have no idea, but draining, drying and cleaning out the tank solved it.

After solving this issue the mover worked fine for another season then started doing it again. This time I went straight to clean out the tank and it fixed again.

I'm frankly gobsmacked that with all the bouncing around on rough ground it could reliably take so long to block the outlet but that's what was happening.

Yorston Bill said:

Will do, thanks for the advice. I haven't changed the filter yet, undergoing chemo so got good and not so good days.

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Sorry to hear of your illness and hope the nausea and fatigue subside quickly.

I had a comparable situation once with a JD. It turned out to be the vent on the gas cap being clogged just enough to interrupt the fuel flow. It would stop after several minutes, then air would slowly repressurize the tank over a little while (15-20 minutes), then it would start and run for another several minutes. Cleaned out the vent on the gas cap, all good after that.

I had a similar issue with a JD RX75. The difference was that it would die after 20 or 30 minutes and then after a 5 minute break, it would run again for another 4-5 minutes. I finally figured out that it was a fuel flow problem. It was gravity fed and the drop from the tank to the carb was very slight, so when the tank got low the fuel pressure only permitted a drizzle of gas to get to the carb. It wasn’t enough to keep up with the demand from the engine so it died of fuel starvation. But let it drizzle for 5 minutes and it filled the float bowl and then the mower would run for a few minutes. In your case, you can run it for 20 minutes after it cools down, so it isn’t just running off the fuel in the float bowl. If the filter is restricting fuel delivery then why wouldn’t it restrict it for the 20 minutes when it does run? I think Rivets is on the right track. You need to eliminate a failing coil as a possibility. Suggest you invest $10 in an inline spark tester and see if the coil puts out spark after the machine shuts itself down. BTW, I’d also install the recommended fuel filter in any case.

Sending strength and best wishes. I’ve been where you are.

Perhaps the magneto module fails when it gets hot. You may replace the module and you can install a toggle switch in series in the "kill" wire that goes to the module. That way you can take a "safety" switch out of the circuit in case a switch fails when it gets hot and switch all that back in when you want to shut the engine down. The misfire sounds like an ignition issue to me.

StarTech said:

According to the IPL this engine came the 70 micron White pancake filter per the PN. Now the Red pancake is a 150 micron filter. Many paper type are in the 25-30 micron range. Depending if the tank bottom is above the engine's top then these 25 micron filter usually still wok fine. I run a Briggs 33 series that is gravity fed without any problems using a 27 micron filter.

Click to expand...

Sounds like a coil problem

Take a piece of cloth cut in 8" diameter circle, remove the fuel tank cap and replace with cloth held on with rubber band. If motor then works fine for long periods you may then want to get a new OE gas cap. Have had this problem on mowers and cars way back into the 70s. Usually a blocked fuel line issue. Most recently last summer with a Broadmoor. Run great for variable short periods then die, however disconnect fuel line from pump input nipple and gas would come out of line, and remove fuel line on output side of pump and get a gusher. Watched a youtube video from "individualized repair" guy showed a zero turn with same problem, gas oozes thru the blockage which makes mower seem to be working fine until a consistent high demand like spinning blades and operational speed has been put on it. So pulled my tank out, more than a little work,and discovered a small piece of paper coiled into a cone like form stuck in the end of the little fuel inlet to gas line, and a dead bug.

Yorston Bill said:

I bought a used Cub Cadet CC30H, it starts and runs well for about 20 minutes, then it misfires and dies. I have fresh fuel, new fuel & air filter, new spark plug and oil/filter change.
After about 10 minutes it starts and does the same again. I don't hear a hiss after it dies and I loosen the fuel cap so doubt that's plugged. When I replaced the fuel filter I did install a paper element filter vs a red screen type, could that be a cause.

Click to expand...

Did you install the filter in the direction of the arrow?

I finally got the filter replaced, used a red 150. Ran the mower yesterday with no issues. Hopefully this issue is resolved. Thank you all for your suggestions, if the problem re-emerges I will return to tis thread and try again.