440 flooding...

  • Thread starter Blinky
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Blinky

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My 440 just quit yesterday AM after running long enough to make a small undercut. Acted like idle was set too low and puttered out, wouldn't restart even after I reset the mixture screws to factory.
Last time I had trouble with this saw it was the fuel tank vent getting clogged so I checked that, took the carb off and checked the bottom screen, all clean, put the carb back on. It started but revved way up until I killed it. Did that a few times until I found the idle screw was in too far.
I'd noticed the carb accumulating raw fuel outside the throttle butterfly before taking the carb off but figured it was related to the idle being way off. I reset the idle and it hasn't started since but it's filling the intake was fuel every time I crank it.
The mixture was tweaked, I have a Max Flow filter on it and sprung for a tach a while back, but it wasn't far off the factory 1/4L and 3/4H.
Last time I used it was a week ago and it was slinging chips like crazy.
 
Sounds like there is crud somewhere. The issue with the settings you stated is that w/o know where the stops have been set to prior to you tweaking the screws! Man I dislike those plastic stops. I would bet some engineer thought the plastic stops would make the shops money. Fooled them didn't ya Chip!!!
 
After fighting with that damned 200t carb, cleaning it three times to FINALLY get all the crap out of it, I'm scared to even offer a suggestion! That thing made me look like a fool!
Try getting some good carb cleaner, Berrymans etc., and clean it out good, look everything over good while you are in there. I try not to use compressed air on them anymore because I can't remember, don't know, which ones have accelerator pumps and which don't. I KNOW the 200t has one and compressed air will destroy it, so I try to just use the pressure from the carb cleaner anymore.
 
When it changes all of a sudden like that, it usually means there's some crud or other blockage somewhere in the carb. I'd try a thorough disassembly and cleaning of the carb. Also check your fuel and impulse lines while you have the carb off (I do that every time regardless).
 
Sounds to me like something is preventing the fuel lever from closing .It doesn't take very much .
Now if you were to by chance get the spacer gasket installed on the wrong side of the diaphragm that will flood them in a heart beat .I'm not laughing if you did because even I who knows better has had head in azz and done it more times than I recall .
 
I had a very similar problem with a saw recently. It turned out that the gasket under the metering diaphragm had a little hole in it that lined up with a hole in the top edge of the carb, and that acted as a vent for the diaphragm, not the usual where the vent is the hole on top of the carb. The gasket was on wrong, so with no venting the saw will soon flood like that and not start or run for more that a second or two. The intake filled up with gas as you describe. Simple, but it took me two days to sort that out. Sounds like possibly a metering problem.
 
The way I read it was that the saw was workin' fine then started acting up. Not after a rebuild.
 
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  • #8
No rebuild, I didn't move the gasket this time but I did a few months ago but the saw's been running great up till now. I'll tear the carb down and clean it thoroughly in the AM.
 
The inlet needle can lose it's proper seating capacity. That would cause flooding. Metering lever too high too.
 
If it has been running perfectly for six months then it definitely isn't the height of the metering lever. This is how people create multiple problems, by adjusting stuff that doesn't need adjusting. I would suggest that any adjustment of the metering lever height before finding the true cause of the problem will result in never being able to find and correct the problem. Do not screw with stuff that isn't broken until you fix the problem first.
 
Right, I was just thinking that Chip may have tweaked it when working on the carb after it stopped running properly, or the spring is out of place if he has done some disassembly.

Lots of my own carb complications have been self imposed. :roll:
 
Skwerl said:
If it has been running perfectly for six months then it definitely isn't the height of the metering lever. This is how people create multiple problems, by adjusting stuff that doesn't need adjusting. I would suggest that any adjustment of the metering lever height before finding the true cause of the problem will result in never being able to find and correct the problem. Do not screw with stuff that isn't broken until you fix the problem first.
Click to expand...

Have to agree with Brian again on this one. The inlet needle is supect from the sound of it but some crud may have gotten past the inlet screen on the pump side of the carb than has allowed the needle to not seat all the way down.

I would take the carb apart and give it a good cleaning before you go adjusting things. I hate taking apart carbs as it is especially the metering side but the only way your going to know if the needle isn't seating is to take it apart and look down the inlet passage making sure it is clear and free of junk. If the saw has been running good the needle itself shouldn't be missing anything from the bottom of the needle or be deformed,but it can happen.

Aren't two strokes fun, never seizes to amaze me how they can run good one day and then all of a sudden start to run erratc.
 
If there is crud in the inlet needle passage, disassembly may not be required. Push down on the metering lever and shoot some carb cleaner in there, then maybe give it a shot of air. That should maybe displace the crud.

The fact that the intake fills with gas so quickly seems like a problem more than just a little crud.
 
The good part is that 2 stroke carbs are a simple design. So taking them apart and cleaning them is a snap. Plus a rebuild kit for that carb is cheap and easy to replace if needed.

Check your inlet screen in the carb is my guess...

Gary
 
It's surprising that the screen will catch stuff that gets by the fuel filter but it does .Never by the way ever remove a carb screen because it's your last line of defense .
 
  • Thread Starter Thread Starter
  • #18
It's back up and running now. I'm guessing trash blocking the inlet needle open but I never saw a speck of dirt or crud in there. The needle does have a groove around it where it seats though. I just started using a Max-flow filter I got from Madsen's and I may have let it too get dry. I didn't oil it before i used it this time.

It's a Walbro carb, how do you get those plastic limiter things out of it?
 
Stihl actually has a tool that removes the limiter caps. Or most people just jam a drywall screw in there and pull. However, you can damage the cap if you use a drywall screw.

Gary
 
If it's a plastic limiter cap, I snip them off with some wire snips, which cracks the plastic and then they come off easily..
 
  • Thread Starter Thread Starter
  • #21
It'll be the drywall screw thing, they're in a recess.
 
You just have to make sure you reinstall them. There are no "springs" in there anymore. If the cap is not replaced the needle can turn on it's own from vibes. While you got 'em out of there... trim off the limiting "tabs" before you put 'em back in.

Gary
 
Just wondering out loud here. Can you take the springs off a old parts carb on the shelf and put them on the L and H after you remove them out all the way. That way you dont have to reinstall the plastic caps.
 
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