Need info on a K301A.

[Dave Brestensky]

I have some real issues I believe with my cub 128. I mowing in some heavy grass last week and stalled the tractor. After that it seemed as if I had a gas issues. It kept stalling out after I made about 3 passes in my gard. I bought a new carburetor and put it on but no luck. I thought it might be bad gas so I removed gas tank cleaned the screen and tank but that only fixed some of the problem. It didn’t stall out anymore but it seemed as if the engine heats up and I lose power. It has t stalled out yet but I have disengage the PTO to get the power back but only for 50 yards or so. I am at a lose. Could it be a burnt valve? A bad head gasket? Really don’t know where to look for the problem

[J-Mech]

Ok, so there are several things to go over.
I don't know why people always seem to go through the fuel system backwards, but they do. You say you put a new carb on it (no idea why you didn't just clean and rebuild the old one), and it didn't fix it, so THEN you pulled the tank and cleaned it. Well, how do you know that dirty or contaminated fuel didn't already get in the new carb and plug it up?

SO......
~Did you then remove the new carb and clean it out while you cleaned the tank?
~Did you replace the fuel line?
~Did you tune the new carb, or just take it out of the box and bolt it on?

As far as the stalling:
~Did you verify it was a fuel issue before replacing the carb? Or did you just guess??
~Did you verify it isn't losing spark when it stalls?
~If you pull the choke out during the stall, does it pick up power?
~You mentioned a blown head gasket: You can usually see or hear a blown head gasket. Go look at the engine and see if it has a burnt black spot near the head, particularly on the corner of the head above the exhaust port. Put your hand up there and see if you feel it blowing compression/exhaust gasses out from under the head. If you read the Kohler service manual, pulling the head and cleaning the combustion chamber, planing the head and putting on a new gasket is recommended on an hour of use interval. In other words, you should do it every so many hours of operation anyway.
~When was the last time you performed a tune up? Adjusted the valves? Set the timing?


Could a burnt valve exhibit these symptoms..... yes and no. Most generally on a K series engine the exhaust valve starts sticking in the guide and causes issues. Most people never notice a burnt valve, even if there is one, and generally the gasket blows or the valve sticks in the guide before it gets burnt bad enough to cause issues.


So, do you have a spark, fuel, or a low compression issue?? We can't tell from here, you need to find out. If you need to know how to perform any of those tests, ask and we can walk you through it. Here is a link to the engine manual if you need it.

[Dave Brestensky]

Thank you for that info. I did adjust the new carb that I bought. I haven’t checked to see if I was losing spark. The tractor seems to idle fine. I will have to do those things you mentioned and let you know what I find. Thank you