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Ok, y'all don't laugh at me when you see the picture of the choke link. I was in the field with no internet access and I figured out what the problem was, but I was not aware that the "spring" the choke link was attached to was actually a thermostat. After taking the cover off a million times I finally realized the arm was in different positions and after screwing with it for a while (and probably buggering it up in the process), I thought, "Hunh..... that thing looks like it's auto-adjusting itself." Can't get nothin by me! :biggrin: I had never seen one of those. ANYWAY..... My autochoke is not working and by the time I tried to adjust that rod a million times, it's been bent into a terrible shape. I might need a new one, but looks like the thermostat is built right into the muffler. My parts manual shows the muffler assembly but doesn't show a separate part number for the thermostat. My muffler appears to be a 300G.

My mower was running raggedy with no power and kept cutting out and at some point I realized it was simply getting way too much fuel and running too rich. Ever since I bought the mower used it's been pouring fuel out of the carb and I thought I had the problem fixed. Once I realized it was running so rich and I started adjusting that arm, the fuel leakage stopped. That choke valve just doesn't seem to want to get in the right position. When I get the mower cranked and it's trying to cut out, I can hold that closed with a screwdriver and the mower will run like a scalded dog. But I know that's too lean. Ever which way I adjusted that linkage, it just seemed to allow the choke to flop and bring me back to the "too rich no power" mode. You think that thermostat is bad? Would that cause this problem?

Pics are of bent up rod, open choke and pics ID'ing my mower and engine. When I started, that rod looked factory new, so yeah. :ashamed:

Thanks for the post and the info. I have this same mower and had carb problems. Took it on and off cleaning it 4 times before it ran right. With this new info I think the choke linkage must have gotten bent a little and in the process of removeing it 4 times
got fixed. Sometimes its the obvious that trips us up.

From what I've been reading the thermostat (that black part on the top of the muffler that linkage connects to) often fails and doesn't operate the choke right. I thought you had to replace the whole muffler, but I think I'm closing in on the right replacement part.

Edit: Gah.... I was looking at the wrong part. Looks like that's an assembly, the thermostat comes on the muffler, not as a separate part. I need part 592362 to the tune of 28 bucks plus shipping, unless I buy a used one off eBay which I won't know if the thermostat works or not. That's a long way towards a whole new Predator replacement engine at Harbor Freight. Now if one of you gurus can tell me how to rig this thing into a manual choke so I can get it to run reliably, that'd be the trick.

Actually, if I remember right, the biggest mistake with that setup is it's easy to have the linkage laying the wrong way during reassembly, causing the choke to stay closed. I'll have to look to see if I have one in the yard. I wouldn't worry much about that choke thermostat rod, it bends easy enough by hand, so as long as you didn't damage the bimetallic spring in the little round part on the muffler, you'll be alright.

Ok, i just checked, and you have the linkage right, you just got to re-bend the rod so it looks more like the one in the picture. The way you got it, it is too straight, and pushing too hard on the choke. Got to bend it to shorten it up.

I've bent that thing a hundred different ways. I really think that thermostat in there is no good.

Johns_Pop said:

I've bent that thing a hundred different ways. I really think that thermostat in there is no good.

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Then put some heat on it and see if it moves, and if it doesn't, replace it...!

It moves. I don't think it's moving reliably though because no matter how I adjust the linkage, it's not operating the choke reliably. Sometimes it opens all the way and the mower runs too rich and it floods the carburetor, eventually dying. If I take all the slack off the linkage the choke just flops back and forth and the mower sputters and coughs the whole time and it eventually dies. I can't get it to close the choke far enough to lean out like it should and stay there. I thought about just plugging the choke shut, but then it runs way too fast and I'm pretty sure it'll destroy the engine pretty quick running that fast. Maybe I have a spring issue or a governor issue, but I was so focused on this autochoke linkage that I'm missing it. The thermostat is moving the linkage back and forth as it heats and cools, but I can't get this thing to run worth a darn. I've cleaned the carburetor and everything looks good in there and as I've said, if I hold that choke closed or in the proper position the mower will run flawlessly, so I don't think it's carb related at least internally. Hopefully I'll get a chance to work on it this weekend and I'll post a couple short videos on youtube and link them here. I appreciate the help.

Johns_Pop said:

It moves. I don't think it's moving reliably though because no matter how I adjust the linkage, it's not operating the choke reliably. Sometimes it opens all the way and the mower runs too rich and it floods the carburetor, eventually dying. If I take all the slack off the linkage the choke just flops back and forth and the mower sputters and coughs the whole time and it eventually dies. I can't get it to close the choke far enough to lean out like it should and stay there. I thought about just plugging the choke shut, but then it runs way too fast and I'm pretty sure it'll destroy the engine pretty quick running that fast. Maybe I have a spring issue or a governor issue, but I was so focused on this autochoke linkage that I'm missing it. The thermostat is moving the linkage back and forth as it heats and cools, but I can't get this thing to run worth a darn. I've cleaned the carburetor and everything looks good in there and as I've said, if I hold that choke closed or in the proper position the mower will run flawlessly, so I don't think it's carb related at least internally. Hopefully I'll get a chance to work on it this weekend and I'll post a couple short videos on youtube and link them here. I appreciate the help.

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When the engine is at running temperature, the choke should be fully open and not like you say fully "closed", are you confusing yourself with the throttle shutter..?

when the engine is cold the choke shutter should be closed, and then open up when the engine get's warm. it should not run rich or should flood the carburetor when the choke is open, if the carburetor if flooding then you need to check it out again, (inlet needle valve or float)

"the Bi-metal spring aids the choke in staying closed to augment cold starts and
assists the choke in opening when the engine is warm."

EngineMan said:

When the engine is at running temperature, the choke should be fully open and not like you say fully "closed", are you confusing yourself with the throttle shutter..?

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Maybe, I don't know to be honest. There's a shutter inside the carb that I can't see when the carb is installed on the mower. Then there's a shutter right there on the outside of the carb, which I posted a picture of, that you can see when you take the air filter off. When that is open, the mower runs ragged and gets way too much fuel. When it is approaching closed, the mower runs better, but the spring/arm is allowing it to flop back and forth and it is still too rich and sputtering eventually losing power to where the engine dies. If I take a screwdriver and hold that shutter closed, the mower runs at top speed with no sputtering at all, but it's running to fast for me to just manually close that up. I can pretty much get the mower started whether it's cold or warm, but it just won't run worth a squat. Again, I'll post a video soon that shows what it's doing as I'm sure that'll show much more accurately the symptoms versus my ignorant ramblings. :smile: I understand the basics of how engines operate, but I'm still learning the nuances of all the various systems on all these various mowers. I wish they'd all come up with something that works and leave well enough alone. I've got 5 push mowers, 4 of them the same brand, and every single one of them handle the choke and throttle differently. (sigh) I don't mind learning, I just have a hard time keeping up with all the changes the older I get. :confused2:

Johns_Pop said:

Maybe, I don't know to be honest. There's a shutter inside the carb that I can't see when the carb is installed on the mower. Then there's a shutter right there on the outside of the carb, which I posted a picture of, that you can see when you take the air filter off. When that is open, the mower runs ragged and gets way too much fuel. When it is approaching closed, the mower runs better, but the spring/arm is allowing it to flop back and forth and it is still too rich and sputtering eventually losing power to where the engine dies. If I take a screwdriver and hold that shutter closed, the mower runs at top speed with no sputtering at all, but it's running to fast for me to just manually close that up. I can pretty much get the mower started whether it's cold or warm, but it just won't run worth a squat. Again, I'll post a video soon that shows what it's doing as I'm sure that'll show much more accurately the symptoms versus my ignorant ramblings. :smile: I understand the basics of how engines operate, but I'm still learning the nuances of all the various systems on all these various mowers. I wish they'd all come up with something that works and leave well enough alone. I've got 5 push mowers, 4 of them the same brand, and every single one of them handle the choke and throttle differently. (sigh) I don't mind learning, I just have a hard time keeping up with all the changes the older I get. :confused2:

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You can see the choke shutter in your second photo, yes the one on the outside of the carb, if it runs ragged and gets too much fuel then there is something wrong with the carb. also check the gasket. (O ring)

Here's the video finally:


When I took the carb off the first time, the float was held in place by a pin on each side. One of the pins had come out of the holder and I snapped it back in place. I didn't think to run a wire in that hole to clean that out though, so maybe I need to take it back out and do that. The gasket looked good and in place, but I didn't "inspect" it, nothing looked out of place, so I didn't bother anything in there. I'll open it back up and take another look at the carb unless this video shows something glaring to you guys.

Yes you have a carb issue. When you take the bowl off the bottom you will see a double nozzle plastic piece in there. Very carefully take that out and then clean all the passages. The o rings on that might be bad too. A new jet assembly is about 10 Bux. You can pop it in and it will run like new ~!~!

The main jet part # is 592792 Regular altitude if you are way up in the mountains then you have to get the high altitude jet.

I just re read your post. Did you say the FLOAT BOWL was held in by 2 pins ?? Only one in my days of working on these newer E series ~!~!

Your pin could be broke and that very well could be your problem Mon Ami ~!~!

I think what's tripping everybody up, is that you said a couple times, "when the choke is open all the way, it runs too rich (gets too much fuel)" (paraphrasing there). That just doesn't make sense. The engine gets more fuel (runs richer) with the choke closed. Like when it's cold, the choke closes, making the engine run richer, and when it warms up, the choke fully opens, leaning out the carb (less fuel), so it will run normally. If you are getting too much fuel with an open choke, that has absolutely nothing to do with the choke.
HOWEVER... If it is warm out, or the engine is warm, and you have to choke it (close the choke) to get it to run right, that means it isn't getting enough fuel with the choke open, likely due to a dirty carb, or some blockage somewhere in the fuel system, like a clogged jet, or a collapsed fuel line, or dirt in the tank, or old fuel.
The only time that choke should ever be closed is when it's cold.

I do have to admit, although I can do minor repairs and I do understand how a 4 stroke engine works, I'm certainly not a small engine mechanic by any means and I'm sure the terms I use are probably incorrect. Not the bowl, just the float.... the float, what I'm *calling* the float is a white piece of plastic and a single pin goes through it which snaps into a channel on each side. When I take it apart, I'll provide pictures that will show my incorrect descriptions. And Zman, I guess you're right, I even thought about that yesterday when I told my son it was getting too much fuel..... I was like, wait..... what? I'll try to get it back open this afternoon, check those jets and take some pics of the inside of my carb. I appreciate everyone's patience and help!

I transposed it. I mean't BOWL FLOAT or the white float.