414-8 starts to die after running 45 to 60 mins

[ericksen 1]

I have a 414-8 (Model No 31-14K804) with the Kohler Magnum 14 HP engine (1200 hours on the mower). The mower starts fine and will run and mow with no problems for 45 to 60 mins and then will start to die. If I apply about 1/2 choke for a couple of seconds, the mower will kick back up and run for another 15 or 20 mins and then repeat the sequence. This will continue a few times until the mower finally dies and will not start until it cools down. I replaced the ignition coil a year ago. Anyone else experience this kid of performance.

[702854boy 1,132]

Maybe try taking the gas cap off the next time it does this, some people here have had problems with the vent clogging up and causing it to starve for fuel unless choked.

[SylvanLakeWH 32,328]

 

And, clean up the fuel system. Clean Carb, replace fuel line, filter, petcock, clean tank. They can all get gunked up...

[gwest_ca-(File Mod) 12,480]

As careful as I am with fuel hygiene I was surprised to see how much crap had accumulated in the tank after thirty years.

[sqrlgtr 3,813]

9 hours ago, ericksen said:

I replaced the ignition coil a year ago.

 

If ignition coil/module was a cheaper aftermarket one I would be suspect of it. What where the symptoms for changing ignition coil in fist place?

 

All of the above Plus

Also, I would clean up entire fuel system and replace all of the fuel lines. I use 100% pure gas in all of mine buy PO's probably didn't on most of them and have found that old fuel lines were breaking down and filling carb and fuel pumps up with trash, this has become automatic now when a new mochine comes into my possession .

 

[953 nut 68,912]

8 hours ago, 702854boy said:

with the vent clogging up and causing it to starve for fuel

The science behind this is that as the engine consumes fuel unless there is a vent to allow atmospheric pressure to push against the gas in the tank the vacuum created in the tank will become too strong for the fuel pump to overcome. A new fuel cap should do the trick.

[pfrederi 21,101]

Looking into the tank at the screen is misleading.  I looked at one that seemed fine.  but when I pulled it out there was a thin coating of gunk