Grasshopper 725, runs 20-30 min then dies

[gstrom99]

Here are a few pics I could get today

That coil doesn't look original. Quality is suspect. I'd try a new (good brand) one.

 

[jorswift]

That coil doesn't look original. Quality is suspect. I'd try a new (good brand) one.

Have put 2 different coils on and both test out good per meter and testing.

 

[jorswift]

I just replaced the distributor cap and it the mower stopped/failed within 10 minutes of running.

 

[duffer]

Just watched a YT video on a mower with the same symptom. Turns out (in this case) it was a faulty gas cap that wasn't venting. After a time of running, it creates a vacuum lock and won't let gas flow to the carb. Try drilling a hole in the gas cap, or in the filler neck right below the gas cap to vent it.

No guarantees, but worth a shot.

 

[jorswift]

Just watched a YT video on a mower with the same symptom. Turns out (in this case) it was a faulty gas cap that wasn't venting. After a time of running, it creates a vacuum lock and won't let gas flow to the carb. Try drilling a hole in the gas cap, or in the filler neck right below the gas cap to vent it.

No guarantees, but worth a shot.

I thought about the fuel pump. I took the hose off and it’s pumping fuel to the carb. So shouldn’t be the gas cap. It’s stuck right now in the drive, so hoping it was an easy fix

 

[jorswift]

Just did it again. Coil is cool to the touch. Had spark for a few seconds right after it died, now nothing. Maybe a temp sensor bad causing it to shut down as it thinks it’s over heating or something? Temp gauge shows it’s in normal operating temperatures.

 

[MinnesotaEric]

Read the title, and instantly wondered if your gas cap's vent is clogged.

 

[jorswift]

Read the title, and instantly wondered if your gas cap's vent is clogged.

No, left the gas cap loose last time and still did it.

 

[kirkawilson]

Could be the wires are breaking down. Start by replacing the coil wire and then the plug wires.

 

[MinnesotaEric]

No, left the gas cap loose last time and still did it.

Vent clogged in the carb? It needs atmospheric pressure on the bowl.

 

[jorswift]

Vent clogged in the carb? It needs atmospheric pressure on the bowl.

I don’t believe it’s fuel related. As spark disappears after warm or hot

 

[MinnesotaEric]

I don’t believe it’s fuel related. As spark disappears after warm or hot

A common problem with tar-packed coils is they warm up and internally short much more frequently than oil-packed ignition coils (wow, now you know I'm old school if I know that, smile).

That said, this thing doesn't have a pickup coil or electronic ignition, does it? They too can work fine when room temperature but then have an open when hot and fail.

 

[jorswift]

A common problem with tar-packed coils is they warm up and internally short much more frequently than oil-packed ignition coils (wow, now you know I'm old school if I know that, smile).

That said, this thing doesn't have a pickup coil or electronic ignition, does it? They too can work fine when room temperature but then have an open when hot and fail.

I tested the coil with meter both cold and hot and had same readings. Coil was actually cold to touch when it shut down.

 

[gstrom99]

Is there a "low oil" shutdown on this?

 

[jorswift]

Is there a "low oil" shutdown on this?

Not 100% sure, but oil is good and full.

 

[gstrom99]

Not 100% sure, but oil is good and full.

You should look. If the sensor fails, it could/does cut off the ignition.

 

[jorswift]

You should look. If the sensor fails, it could/does cut off the ignition.

I don’t see an oil sensor on the wiring diagram. Only an oil light.

 

[gstrom99]

I don’t see an oil sensor on the wiring diagram. Only an oil light.

If it has a warning light, there has to be a sensor/switch. Find it on the motor and unplug (or maybe "short it" if it's got two wires). This will eliminate that possibility...

 

[jorswift]

Well I checked all grounds, switches, relays and safety’s. All check out. I replaced the plugs and the distributor and seems to run great again. We shall see. Thanks

 

[MinnesotaEric]

I don’t see an oil sensor on the wiring diagram. Only an oil light.

The oil sensor is what turns on the oil light.