Kohler cv23 runs for few minutes then dies

[jjpalermo]

This is on a 2006 JD L130 w/ 320 hrs TT, 25 hrs SMOH and full tuneup. All electrical safeties have been removed. Gas cap is new (and vented). Fresh, 97 octane fuel in the tank. All fuel lines have been replaced and fuel screen is clear. Fuel filter has been replaced. Fuel pump has been replaced (electric now). Plugs are new, plug wires are new, and plugs are correctly gapped and sparking. New carburetor installed. Carb ground is attached. Carb solenoid wire attached and receiving voltage, and the solenoid valve is opening (as I said- brand new carb). Gas IS getting to the carb.- Carb float and float valve work fine and keep gas in the bowl. Throttle, choke, and governor are all attached, well-adjusted and working fine. Engine starts fine and runs for 5 min or so, then starts to slow down and eventually dies. I can watch as the governor open the throttle when it slows, then it dies anyway with the throttle completely open. When it cools a bit I can get it to re-start, but only till it gets back to full running temp, then it does w/ the throttle open again. If I spray gasoline into the choke valve as it dies it will rev up again- I can do this over and over and keep it running all day long, but the moment I stop it will die again. I can watch the voltage applied to the carb solenoid on a voltmeter and SEE that it varies as the solenoid valve needs to be opened more or less to adjust the fuel sent into the intake. It still seems to be getting starved of fuel and dying when at full temp.

I am out of ideas.

HELP!

 

[denchen]

Going back to basics and bear in mind I know nothing, But, Firstly, as it dies slowly, it sounds like fuel starvation. It could be modern electrics, but 30 years ago I would say it was fuel frosting in the carburettor. But I assume there is no heater to the carb, water or air that has not been connected. So if its not electric,,,,, is it the right air filter, too much vacuum will cause a pressure loss and the temperature will drop due to latent heat of evaporation. ( liquid fuel changing to a vapour). The wrong fuel filter might `starve` the carb, but I guess you have looked at that. Why a new carb at 320 hours, has me thinking, Im thinking the reason you replaced the carb was not the problem, but as I said, what do I know.

 

[JPRambo]

as asked is it starving for fuel? Is the fuel flow to the fuel bowl restricted? remove the bowl and check float and needle valve. I just had the same problem. Now i have another. ( I may be a bad magneto).
Mine runs good for +-5 minutes then looses power and stops. Will not restart till cool. Good fuel flow and no spark.

 

[denchen]

Again an old fashion answer, but is the `condenser` on its way out. I`ve known condensers to `warm` up then create too much resistance, so stopping the spark going to the coil/plugs.

 

[JPRambo]

How would I check the condenser?

 

[denchen]

I don`t know your engine, or your electrics. A condenser used to be in the old style distributer, a cheap item that was changed about every other time the `points` were changed. At a guess if you had a spare plug, run the engine until it stopped then take of one of the plug leads and connect your spare plug. Ask a mate to crank the starter whilst holding the side of the plug on the block. Better make sure you hold it in a good bit of dry paper or rag, or you will get a belt. If you have no spark, at least you know the trouble is some where there.

 

[JPRambo]

Okay I used one of the plug wire to spark plug lights and no spark. but after the engine cools for a few hours it will start up again.

 

[JPRambo]

but it will have to wait for further work. I as off to california for a couple weeks.

 

[RandyT]

Some of those early Command engine has a Spark Advance Module(SAM) that could be acting up. Those for the most part have been obsoleted and have been replaced with a new ignition system that does away with the SAM, so to assist I will need the Spec number off of the engine model number plate to see what is available and possibly what kit is required to convert your engine to the new ignition system.

 

[jaxs]

jjpal,let's try a couple of things to see if they reveal a clue. Contrary to popular belief,the carb solenoid does not regulate fuel flow while engine is running. It's single purpose is preventing backfire by closeing off flow from bowl through jet when key is turned off. The float,needle and seat regulate fuel level in bowl while engine is running,,AND,,prevent's continued flow and flooding while engine is off. Therein might be the problem. This statement lead's me to think that. "I can watch the voltage applied to the carb solenoid on a voltmeter and SEE that it varies as the solenoid valve needs to be opened more or less to adjust the fuel sent into the intake." That shouldn't happen,it should have 12v when key is on (holding valve open) and no voltage when key is off (allowing valve to close). You sound like a pretty good mechanic and probably know where to go from here but I will tell you anyhow. Check both -&+ wires to solenoid for poor connnections that is allowing voltage to vary. You might also remove valves from old and new carbs to bench test so you can see valve plunger move. While solenoid is out of carb,hold a container beneath bowl and turn fuel on. You have a manual stop valve in line don't you?) If not,install one to make life easier from now on. Gas should continue draining until stop valve is closed or tank is empty. That 100% confirm's uninterrupted flow from tank to bowl. BTW,if both solenoids appear to malfunction,sacrifice one by removing stopper/plunger and using valve body to plug hole until you can get a new valve. If engine backfires when killed,turn the stop valve off and let engine die when bowl empty's. Let us know what happens.