Zama carb issue on Stihl weedeater

[wdfccf73]

Ok, so everyone forgive me I know it's not a chainsaw... However I know you guys are the best!!! So my Stihl FS 55R weedeater quite running. It's hard to start and won't idle.
I got a kit and did a full carb rebuild on it. I made sure everything was clean and blown out before it went back together. STILL NO DICE!!!
It will start and run as long as you 've got it held wot (it's not putting out the rpms it's suppose to) but as soon as you let off it dies!
However if you barely bump the primer bulb it will rev (normal rpm s) like it's suppose to until you let off the throttle.
I even tried adjusting the carb H & L, no luck...
The LA makes no difference either. Screwed all the way in it still won't idle.

Thanks for any help!!!

 

[w8ye]

I have a 55R and went trough all the same stuff

Bought a new carb from Stihl for $28 and all was forgiven. No More problems

 

[tpope]

My FS106 quit running while I was using it last weekend. I was hot and just put it up. Got it back out to use yesterday. It would barely run, run good for a short while and starve for fuel mid cut. Pulled the top of the Zama and found that the needle was binding. Took it apart and put it back together. Everything looked fine. We ran almost 2 tanks of gas with zero problems.

 

[BloodOnTheIce]

I have a 55R and went trough all the same stuff

Bought a new carb from Stihl for $28 and all was forgiven. No More problems

On these I check compression, spark, pull the muffler screen and if those are good.
I put a fuel filter, spark plug, and carb on them and they're usually back running perfect.

The part number you want for the fully adjustable carb is 4140 120 0619

 

[Den69RS96]

Had a similar carb problem on my km 110r. Cleaned it 3 times but it just never ran right. The tuning screws didnt make a difference. So i went to my dealer for a carb kit. My dealer won't stock carb kits. Says its just a temp fix. I bought a new carb and fired right up. Still not thrilled that a $300 trimmer needed a $55 carb when it's only 3 years old, but I'm not paying 26 bucks a gallon for stihl motomix either.

 

[BloodOnTheIce]

Had a similar carb problem on my km 110r. Cleaned it 3 times but it just never ran right. The tuning screws didnt make a difference. So i went to my dealer for a carb kit. My dealer won't stock carb kits. Says its just a temp fix. I bought a new carb and fired right up. Still not thrilled that a $300 trimmer needed a $55 carb when it's only 3 years old, but I'm not paying 26 bucks a gallon for stihl motomix either.

3-5 years is about what most carbs are lasting on the E-10 fuel we have.
The only carbs that seems to clean up well that I commonly see
are Walbro WT, and HD Tillotson RK, and HU, and Zama C3M.
I haven't cleaned a string trimmer, or blower carb in 3-4 years, since the most expensive one is around 50$

 

[morgaj1]

I agree. I have all but given up on rebuilding the small zama carbs. You can usually get a new carb for $5-$10 more than the rebuild kit.

 

[maico490]

Sounds like it could be the Main Nozzle Check Valve. To confirm you need a short piece of rubber hose placed over it and you should be able to suck air through it but not be able to blow back.
Details here: http://www.arboristsite.com/chainsaw/145468.htm

Only a few dollars from a Zama dealer but a bit of time to fix.

 

[maico490]

I agree. I have all but given up on rebuilding the small zama carbs. You can usually get a new carb for $5-$10 more than the rebuild kit.

Not true here in the UK but buy your rebuild kits from a carb dealer not the saw dealer for good prices.

 

[wdfccf73]

Update

Here's an update...

Took the carb back apart and adjusted the needle valve. RPM' s returned to normal at WOT, but still won't idle! The primer bulb will only fill half way. I can't tell if it's normal or sucking air at this point... Very frustrating situation! Went by local Stihl dealer and talked to the main tech. He offered little information... No surprise there... He offered to sell me a new carb or a new trimmer though,,, He was to busy to look at it in the back of my truck. We are all very lucky to have this forum and great individuals who are dedicated to helping others here!!! THANK YOU ALL!!!

So I have a few questions... What is a Welch plug? How do you seal it? Using nail polish?
Can I replace the check valve on this carb? (Zama C1Q S97 692) I seen it in another thread. That would be better than buying anew carb.

Thanks everyone!

 

[BloodOnTheIce]

31.25$ retail price on a brand new carb, but if you like frustration,
wasting gas running to the dealer, and time... carry on trying to repair it.

 

[o8f150]

had one in the shop the other day,,, ended up having to replace carb and it was fine then