Single Tuning Screw Adjustment Weed Eater & Strimmer Carburetor (Adjusting only 1 of the 2 screws)

There is two fuel-to-air adjuster screws on this type of Carburetor, but this video shows you how to get results with adjusting just the largest and most accessible of the two.

In this video I'm going to show you how to adjust the type of 2 Stroke Carburetor with a single adjuster Screw. This style of carburettor fits Weed Eaters / Weed Wacker / Line Trimmers/ Strimmer / Brushcutter, but also Hedge Trimmers and some Chainsaws. But aside from what the carburettor fits, we have the single adjuster screw. I have been asked many times how to adjust this type of carb.

Ok, so, the adjustments on these are actually very simple indeed. Much more simple that the type of carburetor with the a 'H' and 'L' screw setting such as what we see on some other chainsaws etc.

First of all then, we will look at how to adjust the High RPM. The following is an explanation of how I do this procedure, and I am NOT saying it the the best or quickest way.

With all safety precautions met, I start the engine. I Revv the engine to MAX RPM. I take an appropriate screw driver to the single adjuster screw at the center of the carb (Not the single screw situated at the top of the Carb. This one is adjusted later!). I then start to slowly turn the screw Anti- clockwise until I can hear the engine start to change it's tone to a Rich/Lumpy sound, and the engine RPM starts to reduce slightly (If I was to keep turning in this direction, the engine RPM would continue to lower and the engine would probably stop due to too much fuel flooding the engine). When I then turn the screw back in the opposite direction (Clockwise) slowly, so I can hear the engine RPM start to increase and become smoother.

If I was to keep turning the screw in this direction then the engine RPM would increase for a very short time before reducing and becoming weaker whilst continuing the turn. This would be due to the engine not receiving enough fuel. So I bring the screw back to a nice medium point somewhere between the two extremes, but, just on the edge of being very very slightly Rich of fuel. This is to make sure that there is a good supply of 2 stroke fuel going into the engine with it's accompanying lubricating 2 stroke oil, but not too much that the engine efficiency suffers for it.

Well, that is the High RPM sorted, now for the Idling Speed. The Idling adjustment screw is the small single adjuster screw situated at the top side of the carburettor, above the High speed adjuster screw that we have just set. So from idling, I screw in the screw (Clockwise) if I need higher idling RPM and outward (Anti clockwise) if I need less idling speed. I usually reduce idling speed enough so that the strimmer head (if on a weed eater) stops turning but maintaining a good RPM, and increase the speed (screw clockwise) if I feel the engine is running very low, of course. It's really that simple!

The Two Stroke Carburetor can seem complicated initially, but with some explaining this can be de mystified.

I hope you find this video useful, and I really hope you enjoy it.

Many thanks indeed

Craig Kirkman (Owner and Creator of The Repair Specialist Channel)

#CarburetorAdjustment
#2StrokeCarb
#WeedEater
#ChainsawCarburetor
#StrimmerMaintenance
#EngineAdjustment
#CarburetorScrews
#HighRPMAdjustment
#IdlingSpeed
#DIYMechanic
#EngineTuning
#SmallEngineMaintenance
#ChainsawTips
#WeedWhacker
#EnginePerformance
#CarburetorExplained
#2StrokeEngine
#CarburetorScrew
#CarburetorTutorial
#DIYEngineCare

[TheRepairSpecialist]

Note: HIDDEN LOW SCREW! Hi guys. What I should have mentioned is that these carburetors, on these strimmers have two adjuster screws. The one shown, as well as a tiny screw at the very top of the carb. I didn't include the adjustment of the latter screw because i was trying to keep my explanation simplistic. The adjustments I made in this vid are a more common, quick adjustment, but if this does not correct your adjustment issues, then the other screw at the top will need to be adjusted. I will make a video on how to do this. Thanks and sorry I didn't include it in this video. Craig

[juicyfruit-kqbo]

You have just saved my strimmer from the scrapper! The engine kept cutting out and I tried everything new plug, new fuel filter but no luck but I found your video and I turned the screw just a fraction to the right and now it's running fine I can finally cut the grass, Thanks very much!

[noahhamilton]

Was just about to go to work on my weed wackers carb, very clear and digestible explanations that will be very appreciated by me in the next 35 minutes as I rebuild this carburetor. I’m sure it will be appreciated by others as well. Thanks man! Keep up the good videos!

[Pablo-ijm]

Thank you friend. It was the first time I found someone talking about this carburetor.

Thank you very much.
I'm talking about Penha Beach SC - Brazil

[nwsights]

Single screw? What about the tiny hidden screw at the top of the carburetor? It's usually hidden under a little rubber piece inside the gold circle piece on the throttle cable hookup.

[PatGreen]

I learn best from your pictures. The pictures help me understand what each piece does.

[bigdan]

Thank you for this! Just the right amount of detail and brevity.

[misopo]

Thank you for your tips, helped me a lot with setting up the new trimmer

[StephenRandall-xs]

Just found this after repairing a friends trimmer(bmc g wizz make) which had been stood for a while.Evenrually found the fuel pipe in tank had split so would not prime up unless it was tilted.Just fitted new and ran up engine but struggled to rev, tweaked thus screw and improved it but this video will be a big help to re adjust settings as i have no owners manual, , thank you .

[andrewcostello]

Great video, really explained clearly, just set my echo strimmer up, running great now.thank you 👍

[motionhits]

Thanks for the explanation, animation exsaples make it much easier to understand...
Keep going

[johnsomerset]

A great video. Thanks a lot. Incidentally, my hedge trimmer had the adjusting screw in a recess and with a pacman head (slot on one edge). So I jammed a nylon rawl plug onto its 5mm dia head and unscrewed it fully and then cut a slot in the top for a normal screw driver to fit, as I don't have a pacman screw driver.

[JOEZEP]

Been doing this for awhile but always enjoy your videos. Nice work. I believed I mentioned this before, wish I had something like your channel years ago. Would have saved so many hours. But a lot of newbies still have to learn & some of us older guys getting a refresher.
Stay well, Joe Z

[bimalnandana]

Very helpful to understand your creative video with well explanation .Thank you very much .

[The-Mandolorian]

Really clear and informative video.
Thank you.

[mammothmotouk]

Cracking video. Very happy with that.

After a day tinkering with my strimmer getting it to run right.

Your video did it in minutes.

Subscribed!

[gregoryross.]

Thank you for sharing your knowledge. Now I know how to adjust my trimmer carb mixture screw.

[SagarKadam-pf]

Hello.Thanks.I was looking for a video of this type of carburetor tuning for a long time and found it today.Thanks again.

[leeBoB]

Best video channel on YouTube. Thanks very much.

[chrisjones-drdb]

Love your video simple and easy to follow and understand from Sydney Australia cool keep going thanks