Weedeater mixture screws - how to adjust?

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  #1  
Old 05-16-10, 12:01 PM
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Weedeater mixture screws - how to adjust?

Anyone have any idea how to adjust these screws? They have a weird head on em that makes it difficult to adjust. Check out the photo:

http://i799.photobucket.com/albums/y...eaterLarge.jpg
 
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  #2  
Old 05-16-10, 01:56 PM
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You can get a tool that will fit them or for a cheap fix use a crimp on wire connector of that size. Since you really don't have to fool with it that much, I would use the wire connectors.
 
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Old 05-16-10, 04:21 PM
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Well I'll tell ya...

The reason those screws are tough to adjust is two fold...
1: the Epa back in the 90's began requireing tamper resistant fuel mixture adjustments on all 2 cycle engines for emissions reasons.

2: The manufacturer Wants the factory preset to remain for several reasons
A: most people start fiddeling with the mixture instead of cleaning or replacing filters...filters get clogged, impede airflow so the user leans out the mixture till it seems to be running good..Then they do it again... and again...Then finally they'll replace the filter , and low and behold ..a whoosh of fresh air combined with the lean set carb cause a condition of fuel starvation...she revs like a wild cat and... toasts the rings and cylinder wall... a fry'd cylinder from fuel starvation looks very differint from one that ran straight gas (No 2 cycle oil)

A fuel starved cylinder will only be burnt and scored on the exhaust side of the cylinder as the carb side recieves enough liquid to cool and lube that side , but the entirety of the mix is combusted before any liquid fuel gets to the other side , hence no lubrication on the exhaust side of the cylinder.

A straight gassed cylinder will be roasted anywhyere or everywhere in the 360 degrees of the cylinder wall...

Adjusting the mixture is much trickier in a 2 stroke engine than a four stroke, and can have disasterous consequences....Try to keep the air and fuel filters clean instead
 
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Old 05-16-10, 05:05 PM
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Originally Posted by marbobj View Post
You can get a tool that will fit them or for a cheap fix use a crimp on wire connector of that size. Since you really don't have to fool with it that much, I would use the wire connectors.
I got one for under 10 bucks on ebay
 
  #5  
Old 05-16-10, 06:13 PM
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What did you search for to find that tool 38?
 
  #6  
Old 05-16-10, 06:35 PM
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Originally Posted by 38racing View Post
I got one for under 10 bucks on ebay
I think the below item is about $1, force one on, remove the screw, cut slot with a dremel and your good to go. Have a good one. Geo

 
  #7  
Old 05-16-10, 06:50 PM
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Originally Posted by TheBlackLab View Post
The reason those screws are tough to adjust is two fold...
1: the Epa back in the 90's began requireing tamper resistant fuel mixture adjustments on all 2 cycle engines for emissions reasons.

2: The manufacturer Wants the factory preset to remain for several reasons
A: most people start fiddeling with the mixture instead of cleaning or replacing filters...filters get clogged, impede airflow so the user leans out the mixture till it seems to be running good..Then they do it again... and again...Then finally they'll replace the filter , and low and behold ..a whoosh of fresh air combined with the lean set carb cause a condition of fuel starvation...she revs like a wild cat and... toasts the rings and cylinder wall... a fry'd cylinder from fuel starvation looks very differint from one that ran straight gas (No 2 cycle oil)

A fuel starved cylinder will only be burnt and scored on the exhaust side of the cylinder as the carb side recieves enough liquid to cool and lube that side , but the entirety of the mix is combusted before any liquid fuel gets to the other side , hence no lubrication on the exhaust side of the cylinder.

A straight gassed cylinder will be roasted anywhyere or everywhere in the 360 degrees of the cylinder wall...

Adjusting the mixture is much trickier in a 2 stroke engine than a four stroke, and can have disasterous consequences....Try to keep the air and fuel filters clean instead
I have posted what you are talking about, many times. The first thing a lot of people do with a bad running engine is get on the carburetor screws.
When I encounter a carb. related running problem, I remove and rebuild the carb. and put the adjustment screws back, basically, to their original adjustment.
I have received a lot of disagreement with my statement "there is no periododic adjustment to a carburetor.
May not work for all--But it works for me
 
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Old 05-16-10, 06:56 PM
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Originally Posted by marbobj View Post
What did you search for to find that tool 38?
marbobj;
Just search "carb tools" they will show up, a set is about $30, I have a set and have used them once, it is easier to have a couple electrical connectors in my tool tray. Have a good one. Geo
 
  #9  
Old 05-16-10, 07:49 PM
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My Weedeater has never run quite right.......it's actually a strange problem. It's only 2 years old and I've taken good care of it, draining the gas every season and using stabilizer in the gas.

I can get it started up no problem and it seems to run good for a little while and then it starts acting up a bit.

It has a hard time running full throttle and will usually bog out at some point. It can never seem to recover from the bog and no matter how much you finesse the throttle it just wants to die......and eventually it cuts out. Gotta try and start it up again and it's fine for another little while but it will happen again.

My yard is pretty small and I can usually do everything I need to do in about 15 mins, but the weedeater will die out on me 3-4 times a session.

I've looked at the air filter......it's perfect. I've also checked the gas cap, it's venting.
 
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Old 05-16-10, 10:27 PM
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Cracked fuel lines or primer? If not, it's likely developing an air leak when it warms up. The crankcase cover is cheap plastic, and as it warms, it expands and can warp and leak air into the crankcase...causing your problem.
 
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Old 05-17-10, 08:01 AM
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That's interesting.....

Is this warping crankcase cover a common problem?
 
  #12  
Old 05-17-10, 09:31 AM
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When the engine starts stumbling spray some carb/brakeparts cleaner behind the carb and along all mating surfaces of the crankcase, if the engine tempo changes you have found an air leak and can take the appropriate action. Have a good one. Geo
 
  #13  
Old 05-17-10, 01:43 PM
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Originally Posted by geogrubb View Post
marbobj;
Just search "carb tools" they will show up, a set is about $30, I have a set and have used them once, it is easier to have a couple electrical connectors in my tool tray. Have a good one. Geo
when the engine is running you can slide the tool over the screw and it stays while you adjust. I can't keep a slotted driver in the screw slot when the engine is running.
 
  #14  
Old 05-17-10, 04:52 PM
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Originally Posted by 38racing View Post
when the engine is running you can slide the tool over the screw and it stays while you adjust. I can't keep a slotted driver in the screw slot when the engine is running.
The electrical connector works well when running, the slot makes a good reference if the connector slips. Have a good one. Geo
 
  #15  
Old 05-17-10, 04:58 PM
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Some kind of air leak would certainly make sense.....

When it starts to stumble it's not smoking or anything so it seems to be leaning out to the point where it's barely running. Throwing the choke on might help it, next time it happens I'll try both.

Strange though, it's always done this.
 
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