Flooding Carburetor on a Husqvarna Push Mower with Kohler Engine

[JStevenP]

Can anyone tell me if this problem has something to do with the auto-choke?

I am trying to fix an old (15+ years?) Husqvarna 6021P push mower that has a Kohler Courage XT-6 149cc engine. It had all original parts and was running poorly at the start of the summer. At that time, I discovered for like $2 more, I could get a replacement carburetor, instead of a rebuild kit, so I did. It has been running fine until recently. Now it is flooding on restarts. When the engine is cold, it starts and runs great. Once up to operating temperature, if I shut off the engine, it won't restart. It floods the carburetor when trying to get it started again. I think it may be related to the auto-choke.

Before I spend more money, how do I confirm whether the problem is related to the auto-choke?

 

[mechanic mark]

Free Kohler Service Manual Downloads - OPEengines.com

Listed below are Kohler engine service repair manual in Adobe PDF format that you can download for free. Below we have provided a link to these manuals which can also be download. Click on your engine listed below to download. These service manuals provide general information, adjustment...

www.kohler-engine-parts.opeengines.com

Click above & scroll down page to XT6 & see Troubleshooting, let us know how it goes, thanks Mark

 

[VegetiveSteam]

Sounds like a choke issue to me. Take the air filter off and look and see if it’s closed. How long is the engine shut off before you try to restart it?

 

[JStevenP]

When I run the mower to operating temperature and shut if off, then remove the air filter, the butterfly is usually in a halfway open/closed position. Its only off for a few minutes when I try to restart the mower and it begins to flood. If I use a finger to fully open the butterfly, one yank of the rip cord, and the butterfly goes half closed again. I wind up coming back hours later or even the next day to get it to start again.

I scanned through the recommended PDF file. The choke mechanism is some kind of sealed unit. I don't know what I can do with it, if anything. I see replacements on the internet for like $26, but I didn't want to spend that if there was something else I should be looking into first.

 

[VegetiveSteam]

When I run the mower to operating temperature and shut if off, then remove the air filter, the butterfly is usually in a halfway open/closed position. Its only off for a few minutes when I try to restart the mower and it begins to flood. If I use a finger to fully open the butterfly, one yank of the rip cord, and the butterfly goes half closed again. I wind up coming back hours later or even the next day to get it to start again.

I scanned through the recommended PDF file. The choke mechanism is some kind of sealed unit. I don't know what I can do with it, if anything. I see replacements on the internet for like $26, but I didn't want to spend that if there was something else I should be looking into first.

This engine uses a vacuum choke pull off doesn't it?

 

[JStevenP]

This engine uses a vacuum choke pull off doesn't it?

From what I have read, it is a choke that contains an internal coiled spring (sealed closed with rivets), and the spring behaves like a thermostat. It is mounted to the muffler on the right side of the engine and the heat from the muffler is suppose to cause the internal spring to expand. There is a rod that extends from this sealed unit across the front of the engine over to the left side. So when the internal spring expands, it is suppose to rotate the rod. On the left side of the engine, the rod connects to a lever on the carburetor and the lever, in turn, opens/closes the choke. It's acting like the coiled spring is no longer responding to heat, but with it being a sealed unit, I cannot verify that to be true.

 

[VegetiveSteam]

Yes it is a sealed thermostatic spring coil unit on the muffler but there has to be some mechanism that partially opens the choke before the spring unit on the muffler gets warm enough to fully open the choke. The early Kohler XT engines used a vacuum diaphram pull off or relief to do that partial opening of the choke while the engine warmed up. Once the thermostat coil on the muffler got warm enough, it overrode the vacuum relief. Later XT engines used governor tension to partially relieve the choke. Does your system look like the diagram below? Item C is the vacuum relief I was mentioning.

 

[VegetiveSteam]

If this is the system you have, notice the item circled in red below and shown again in another picture below that. That black plastic flag I'll call it, is able to be removed from the shaft and can be turned to change the clock position to add spring tension when the spring gets older and looses some tension. If you take it off, don't twist it. That flag and the shaft have splines to keep that flag from moving on the shaft. It needs to be pulled straight off so not to damage the splines. You could try taking it off and moving it a spline or two to increase the spring tension. There is also a pretty simple trick done with the vacuum relief that takes up some of the slop those can develop over time. I can go into that later if need be.

 

[JStevenP]

Yes, that diagram is accurate to my setup. So if I make the suggested adjustment, and I do so while the engine is cold, I should rotate the black flange just enough so that the tension is holding the butterfly closed, right? I mean, if the engine is cold, I would expect the tension to hold the butterfly closed and as the engine heats up, hopefully the spline will rotate the black flange in such a way as to open the butterfly and keep it open during operating temps. Am I understanding you correctly?

 

[VegetiveSteam]

Yes. You have to pull the black flange off the shaft and then reinstall it in a new position with just enough tension close the choke. And again, pull if off. Don't twist it.