Strimmer Carburetor Problems

Genuineguy

Hi,
I have a 3yr old strimmers that started to cut out at low revs, I have taken the Carburtor apart and cleaned,

However this Carburetor has no Idle or mixture adjustment on the outside of the Carburetor casing, I re assembled and still at same in that i have to adjust the throttle partially open so as the strimmers does not cut out,

Can someone advice me in how to fix this issue?

I got a guy to look at it last year as there was dirt in the carburetor, And it was loosing power, The mechanic said that these carburetors you have to set the needles in them, that they cant be done from the outside.

celticmicky

Genuineguy wrote: »

Hi,
I have a 3yr old strimmers that started to cut out at low revs, I have taken the Carburtor apart and cleaned,

However this Carburetor has no Idle or mixture adjustment on the outside of the Carburetor casing, I re assembled and still at same in that i have to adjust the throttle partially open so as the strimmers does not cut out,

Can someone advice me in how to fix this issue?

I got a guy to look at it last year as there was dirt in the carburetor, And it was loosing power, The mechanic said that these carburetors you have to set the needles in them, that they cant be done from the outside.

What make of strimmer is it? In some of those carburetors there is a small brass jet inside that can be taken out with a small flat head screw driver wriggled underneath it. If you have a very fine bit of wire, like one strand of a bike cable or something similar, thread it through the jet and rod it a few times (don't over do this as you can easily damage the jet.

This brass jet is not in all strimmer carburetors, if you don't have any luck with rodding it out yourself bring it to your local repair man, it shouldn't be too costly to clean out.

PS is the compression on the machine still good? Sometimes when the compression has lessened on 2 stoke engines they don't idle properly.

slowburner

How is the dirt getting in - is there a problem with the air filter or its casing?

CJhaughey

What brand of carb is it Zama or Walbro?
Generally Strimmer carbs are not adjustable- at all.
Chainsaw carbs have limited adjustment.
Strimmers are designed to operate at a fixed load, saws can have various different bar and chain combinations that will alter the way the saw runs.
Don't use steel wire to clean the jet, it will scratch the jet and ruin the carb.
Use brass wire if you absolutely need to clean it that way, usually what happens is the machine is left with petrol in the carb for a period of time and the fuel evaporates off and the gummy residue left blocks the passages in the carb.
I would see if you can find a place with a ultrasonic cleaner and see if they will clean it for you.
There should be a fuel filter inside the tank, weighted so it stays under the surface. That should stop dirt getting into the carb, if it doesn't change it for one that does.
3 years old with occasional use shouldn't wear it out unless it doesn't have an airfilter.

eth0

Blast it with piss carburettor cleaner. Hard to get this stuff though, dunno any place that sells it

Genuineguy

Hi

The Carburetor i think is a Zama, I have attached two pictures of the carburetor on my strimmers

DSC00043.JPG

DSC00042.JPG

I have cleaned it with Carburetor fluid twice, Diagphram looks good along with fuel pump gasket, When i look into at the piston with a light there is ver fine lines on the pyston wall, I.e. u can see them with the light, Should the piston wall be very shiney to look at ?, I am not sure could it be a Vacumm leak? Any suggestions

Genuineguy

Hi,

Ok the next step is to vacuum test the carb and the engine to see is there a vacuum leak, Does anyone know where i could get a cheap hand held pressure pump with gauge to test the carb for vacuum leak and the engine. I am located in Westmeath, Maybe i can make the device if i can allocate the parts.

CJhaughey

I wouldn't say its a vacuum leak, More likely the buggering around with cleaning has messed the needle valve height up.
The float valve is critical to good running. The diaphragm that moves up and down can go hard from the fuel after a while and not work properly.
I suggest getting a carb rebuild kit and putting a new diaphragm and gaskets in first.
Set the needle valve height, you may need a gauge.
The kit should be cheap less than 15.

Genuineguy

CJhaughey wrote: »

I wouldn't say its a vacuum leak, More likely the buggering around with cleaning has messed the needle valve height up.
The float valve is critical to good running. The diaphragm that moves up and down can go hard from the fuel after a while and not work properly.
I suggest getting a carb rebuild kit and putting a new diaphragm and gaskets in first.
Set the needle valve height, you may need a gauge.
The kit should be cheap less than 15.

Cool over the Xmas i will get a new carburetor rebuild kit,As you say may be an issue with the Diaphragm getting hard. Also setting the needle valve height, how do i do this
Needle Valve carburetor.JPG

Should the Needle valve lever be flush with the Surrounding body?

Thanks

CJhaughey

Genuineguy wrote: »

Cool over the Xmas i will get a new carburetor rebuild kit,As you say may be an issue with the Diaphragm getting hard. Also setting the needle valve height, how do i do this
Needle Valve carburetor.JPG

Should the Needle valve lever be flush with the Surrounding body?

Thanks

You can get a needle level gauge from the same place you get the gasket set.

Nonmonotonic

Good work CJ!

Its so easy, you can do it with a camera in one hand!

https://www.youtube.com/watch?v=CkNgIIIeQS8