K301 Stalling Out, Then Runs, Stalls again...

[ahthurungnone 0]

Finally found a nice C-121 with the Kohler K301 motor. Anyways, very well taken care of but having an issue after running a while...

Runs for 5-15 minutes fine, then starts to studder and possible die. Doesn't matter if it's on flat or angled terrain, smooth or rough surface. 

I can choke it a little bit and this stops it from stalling. However it may or may not regain full power. Acts like its at half throttle sometimes.

Going to do the obvious, new air filter, sea foam in gas, but it seems to be a fuel issue, like its starved for gas which makes me believe it may a fuel filter or carb issue.  Perhaps the ports getting clogged, not sure.

Any help is appreciated. 

[buckrancher 2,694]

check vent in gas cap valve at bottom of tank for flow also at fuel pump before and after (crank motor with line off) be sure short piece fuel line is turned as far away from muffler as possible(vapor lock)

clean carb bowl

and blow out jet ports with compressed air

 

Brian

[daveoman1966 3,828]

Sounds typical of a faulty condenser.  A failing one will be good until it gets warm....then fail, just like you've described.  $4 item at any repair shop.   

[BESTDOGEVER 218]

That is also a symptom of a coil going bad when it stalls out check for spark if its coil or condenser you won't have spark 

[953 nut 58,251]

Like @buckrancher said, I had the same problem and it was the fuel cap not venting.

[1974-B-80 52]

My neighbor has a C-121 that had the same problem. He put a new carb thinking it was that but it turned out that the coil was bad

[ahthurungnone 0]

Found a correct gas cap. Will install that then see about replacing the coil. Thanks everyone. 

[ahthurungnone 0]

Gas cap didn't fix anything. 

I have no idea where the condenser is!

i am no mechanic. 

 

[daveoman1966 3,828]

The condenser (condenser) is a little thingy bolted to the engine shroud nest to the coil.....see in this pic. Over time, these go south.. cheap item is less than 5 bux.

Edited April 30, 2016 by daveoman1966

[oldredrider 2,553]

Not to hijack, but Dave, what is attached to the air cleaner housing?

[ahthurungnone 0]

I was wondering what that little thinking was. Should I replace the coil while I'm at it?  And thanks for the pic!

Listings for the condenser also have points. Should I buy both?

If so, where do I install the points?

[953 nut 58,251]

For troubleshooting purposes you can  disconnect the wire on the condenser from the coil, if you have spark then and it runs better, the condenser was the problem. You shouldn't run it for long without the condenser, but 5 or 10 minutes won't be a big problem.

[daveoman1966 3,828]

3 hours ago, oldredrider said:

Not to hijack, but Dave, what is attached to the air cleaner housing?

I'm not sure.  The air cleaner cover has a short-nipple air pipe and I just covered it with a cap from a 2 gal antifreeze jug.  Maybe that air nipple was for a snorkel....lol.  I've never seen one like this either and I've long since sold that tractor. 

[BESTDOGEVER 218]

I would do the condenser first as it is cheap and accessible  coil next  points either work or not so they would be last.