Hidden 'LOW' Screw on Weed Eater Carbs & Carburetor Tune
ฝัง
- เผยแพร่เมื่อ 18 ก.ย. 2024
- Within some weed eater carburetors, particularly those found in two-cycle engines, you might encounter a "hidden" LOW screw at the top of the carburetor. This screw is typically used for fine-tuning the low-speed (idle) fuel-air mixture, ensuring the engine runs smoothly at low RPMs and doesn't stall when idling.
Here’s some information about the hidden LOW screw and its purpose:
1. Purpose of the LOW Screw:
Low-Speed Adjustment: The LOW screw adjusts the air-fuel mixture for low-speed operation or idle. This is crucial for maintaining a stable idle speed and preventing the engine from stalling when it's not under load.
Fuel Efficiency: Proper adjustment of the LOW screw ensures optimal fuel consumption at idle and low-speed operation, which can lead to better fuel efficiency and longer engine life.
Smooth Running: By fine-tuning the air-fuel mixture, the LOW screw helps the engine transition smoothly from idle to higher speeds.
2. Why is it Hidden?
Emission Regulations: In some cases, the screw is hidden or capped to prevent easy tampering, which can help the carburetor remain within emissions regulations set by environmental agencies. Manufacturers often do this to ensure compliance with these standards.
User Safety: Hiding the screw can prevent users from accidentally adjusting the carburetor settings incorrectly, which could lead to engine damage or unsafe operation.
Factory Settings: Many weed eaters are tuned to specific settings at the factory. Hiding or limiting access to these adjustment screws helps maintain the factory calibration, providing consistent performance.
3. Accessing the Hidden LOW Screw:
Locating the Screw: The screw is typically located on the side of the carburetor, but it might be covered by a small plastic cap or a metal plug. On some models, it is directly accessible from the top but recessed within a small hole.
Removing the Cover: If the screw is covered, you might need a small flathead screwdriver or a special tool to remove the cover. In some cases, the cover might be designed to break off, allowing access to the screw.
Special Tools: Some manufacturers use special screws that require proprietary tools for adjustment. If this is the case, you may need to purchase the specific tool from the manufacturer or an aftermarket supplier.
4. Adjusting the LOW Screw:
Turning the Screw: Typically, turning the screw clockwise will lean the mixture (less fuel, more air), while turning it counterclockwise will richen the mixture (more fuel, less air).
Fine-Tuning: Make small adjustments (1/8 turn at a time) and listen to the engine's response. The goal is to achieve a smooth, steady idle without hesitation or stalling.
Testing: After adjustment, rev the engine to check the transition from idle to high speed. It should accelerate smoothly without bogging down.
5. Cautions:
Do Not Over-Tighten: Over-tightening the screw can damage the needle and seat, causing permanent carburetor issues.
Follow Manufacturer Guidelines: Always refer to the weed eater's user manual for specific instructions regarding carburetor adjustment. Incorrect settings can lead to poor performance, increased fuel consumption, or engine damage.
Environmental Regulations:
Be aware of local regulations regarding emissions. Altering carburetor settings might affect the engine’s compliance with these regulations.
Adjusting the hidden LOW screw can be a useful way to ensure your weed eater runs efficiently and smoothly. However, it's important to make adjustments carefully and in line with the manufacturer's guidelines to avoid potential issues.
Thanks
Craig
Covered all of the bases with fantastic graphics. Who could ask for more ? 5 Stars... that said, I have a 4 stroke Makita Leaf Blower that every 5th or 6th tank of gasoline I run through it I add a tank of 20% or so mix of gasoline and Lacquer Thinner and it keeps my carb clean without needing tear downs due to the poor gasoline quality available here in the Philippines. Just a tip that has solved problems for me. I make sure it doesn't sit in the carb for more than a day or so though, as I'm not sure about any possible negative effects of leaving the thinner/gas mix in for to long. On another note, I always filter my fuel through a surgical mask when transferring from large to small fill containers. Keeps all debris out and removes any water... The manual says the motor is good for 200 hours before needing a rebuild but I'm pushing 800 plus hours and she is still running strong. I change the oil every 5th or 6th use as well. Long Live the Makita... !! Hahahahaha ... a country boy will survive !!
You think the lacquer thinner trick might work in cars also.
What's the 20% the gasoline or the thinner? I assume the it's the thinner.
@@onlythetruth883 ... 20% or so lacquer thinner. As for cars... I wouldn't have an issue putting it in old carburetor style cars but I wouldn't put it in anything fuel injected, especially loaded up with sensors. I ran a good brand (Chevron I think) injector cleaner through my Chevy Silverado years ago and it wiped out a couple of sensors... and the injector cleaner was supposedly safe and made to be used for cleaning said injectors. All this said... again... I would also be careful not to leave it in the fuel system very long, (12 hours or less) as again... I don't know what the long term exposure would/could be to fuel system parts / components. That's just my take... the mileage of others may vary. As for my leaf blower... I haven't noticed any damaged to fuel lines, filters, etc... for what it's worth. They have remained flexible and appear to be unaffected by the thinner. In closing, if I were to put it in a old car, tractor, rotor-tiller, etc... I would make sure I had a GOOD fuel filter installed as it may loosen a lot of gunk and cause problems if said gunk found it's way into the carburetor. Jus' sayin'... and use at your own risk.
Great presentation as usual!!! Still the best instructional and videography on this topic. Many years back the library was
where I got my basic information then hours of trial & error. Your videos are more than classroom worthy.
👍# 144
Stay well, Joe Z
Thank you so much Joe Z👍👍👍👍
@@TheRepairSpecialist You're welcome!
your instructional videos just keep going "over the top", superb presentation with outstanding visual illustrations, thanks for your gift of knowledge to us all.
Thank you so much. I really appreciate it. Craig 👍👍👍👍👍
You are absolutely amazing and true.
Those close ups of the inner workings and added animation give such a clear understanding and develops intuitivity. Thank you so much. I appreciate the work you put in to making this.
Wow, thank you! 👍👍👍👍
Great in depth explanation again from yourself. The time you put into your videos is much appreciated by me and others no doubt, thank you.
I haven't seen any videos that goes into great detail like yours. Thanks.
Thank you so much 👍👍👍
Craig your videos are always spot on and very informative . If you have a poorly running engine even a slight cleaning can be helpful . Craig thanks for sharing 😊
Absolutely, and thank you so much for your kind feedback Artie👍👍👍
Thanks for another informative video. I hadn't thought about air entering at the crankshaft but it makes complete sense the way you explained it. Thanks again & have a great day.
Thank you so much 👍👍👍
Brilliant! Absolutely the best analysis I've seen.
Wow, thanks! 👍👍👍
Excellent video. Brilliant presentation. Thorough and patiently presented. Doesn't get much better than this. Thanks very much.
Thank you so much. I really appreciate it👍👍👍
Outstanding presentation!
Thank you so much 👍👍👍
I wish my school teachers had taught the way you do ! 🙂
Thank you so much. I really appreciate it. Craig 👍👍👍👍
Well presented.
Thank you so much 👍👍👍
Use an induction tachometer and set the idle and high RPM to factory specs using with the L and H needle set
What an amazing creator.
Thank you so much 👍👍
Thank you very much
You are welcome👍👍👍👍👍
Thank you important information
Thank you so much 👍👍
I thank you for this video once again about carb settings. As such I have a problem. Dolmar 114. L screw likes to run on 3/4 out only and the H screw is 1 1/4 out. After 4 mins of usage. The engine is seriously HOT and bogs down and dies. Compression is 120 and in the green. Anyways. Needless to say whilst running the chainsaw. I have noticed a very odd weird running of the chain ITSELF, which happens to my other chainsaw as well. During the run cycles of usage. The chain gets very stiff and tight around the main bar. So, natually I STOP, slacken bolts off and pull back the bar to release tension. Leave it for 20 mins, then come back readjust chain settings. My adjustment method is this as a description. When setting the chain, I always make sure that their IS at least 1mm slack from chain to BAR. I pull the chain by hand and rotate the chain a full 180 degrees. Top becomes BOTTOM and bottom becomes TOP. This is where it gets weird. This rotation of 180 can cause 1 of 2 things. Over tightening of the chain OR very slack chain upto 5-6mm GAP and sag. What the hell is wrong with this. Please understand (Same BAR and Chain) on 2 different chains saw. 1 YATO and the other DOLMAR. I am using a new bar and a newish chain. When I say newish, I am talking about 4 hours old and 2 or 3 chain sharpens later, Also I do have a spare chain which gets swapped out If I forgot my sharpening tools. This also has the same effect
How much chain oil are you using in the 4 minutes,as your symptons seem like a dry chain hence thd heat which can also be due to your chain being too tight. You should havev3 drivers above the bar when you pull the chain up prior to starting work. You can check the oil flow by aoming the end of the bar at either a lump of wood or card and watch for an oil spray being fired out. Hope this helps.
@@johnutting9615 I knew you would say this. As I have said before. This happens on 2 chains saw with the same bar and chain. Anyways. The Dolmar has consumed the ENTIRE tank of oil. 0.7 ltrs. So no over heating of the bar or chain. The Yato will take a full tank aswell to 1 full tank of fuel. Again no oiling issues.
I had this happen on a Jonsereds,I would set the chain correctly next thing ya know it's real tight when I cut,then I would loosen it then it would get too loose and so on back and fourth.Brought it to my work partners kid mechanic and the bearing on the side where your clutch is I think that's what it's called was shot,solved my problem.A person can take it off real easy and the bearing,if a person knew about it ,I think it should be regressed at least once a year,hell I never knew about it,I cut 8-12 cords a year or so,hopes it helps you or someone to check. 23:01
@@gregflorcyk4725 Are you saying the NEEDLE bearin g on the clutch DRUM is fubar. If that is the case I would agree. What I Omitted from my statement is thus... This is a scrap chainssaw. Repiared carb and gaskets. Now running. Unsiezed clutch drum and needle bearing. Will be buying a new drum kit with floating sprocket. Will buy new chain and BAR as those are TOAST. I have got a neew needle bearing but have same results when fitting OLD drum clutch. TIGHT AS FUK!!.. So needle bearing is OKAY but thin it maybe Clutch drum warped and overheated ALOT. Hence needle bearing cannot run smoothly.
HOWEVER, this does not resolve my YATO issue. This un it is brand new but DOLAMR 34 years old was a scrap SALAVGE!!. Thanks buddy, I think you and I have it correct. But wanted to ask a professional. Before wasting and commiting to spending monies.! thanks orz.
I'm by no means an expert,just a thought.Thank goodness for u tube,there's a lot of people out there with knowledge at least gives people ideas to check,take care.
Excellent video. Just what I have been looking for. What is the approximate idle speed for a strimmer like this?
Great video, the carb on my weed strimmer has the small hidden L screw but no H screw. Is there any way to adjust the fuel at high revs on this type of carb?
Best vedio sir,, thank you!!!
Thank you so much 👍👍👍
I had no idea.
Magnific
I disasambled carburator from the engine and there was little fuel near the carburator fuel throttle is it normal ?
Throttle and choke shaft wear is a problem, but the major problem is “human error ” they get doctor google advice and start turning screws willy nilly instead of fixing the problem they cause a new one ……..