Stihl Zama carbs

[Shrewcub]

I was using the Stihl FS-45 string trimmer here at my aunts place yesterday. It fired right up and was a perfect fit for me. 10 minutes later it quit. I put some more gas in it and went to purge the carb. 3 pumps and the bulb got hard like there was a restriction. It was full, so I fired it back up. It idled fine but wouldn't rev up.

I checked the spark arrester, it was fine. Pulled the carb and cleaned it out. Didn't see any issues. Put it back on. Now it won't purge at all. Did some googling and apparently a lot of people are having issues with these cheap Chinese carbs. I believe I have a bad check valve somewhere. I don't have my Mightyvac with me. Any way new carb is on the way. I went with a $20 one. I saw them as low as $12, but didn't like the looks of them.

This has always had straight gas with Stihl oil in it. Just wondering if anyone on here has had issues with these fine Chinese carbs?

[Sam Mac]

Just rebuilt a Zama on a Stihl FS55 weed whacker. Looks pretty much like a Walbro.

[john hall]

Yes, the check valve on a Stihl machine I was working on went bad. At first thought it was the bulb itself. Then I ordered the primer bulb assembly which had the valve in it. Solved the problem. Lately, I price an entire carb before ordering kits. Some OEM carbs can be bought for double what a kit cost, why bother rebuilding. Others are north of $100, then it makes sense to me to rebuild. To each his own in this area.

[mjsoldcub]

Stihl owns zama.....the fs-38 through 55R all share the same 27.5cc motor carb, etc...only difference is plastic, (on the new ones) and whether its a straight shaft or curved shaft, (hate em) trimmer....yes the carbs will fail after awhile especially if they have had ethanol in them... i know you say its had straight gas, but are you the original owner??? i also recommend to treat them with stabil, even if its going right to get used or not....these are cheap carbs a chinese one will be the same whether its 7 dollars or 40, (although this one shouldnt be more than 22$) from Stihl.... they have a little rubber tipped float needle and the diaphrams will actually break down....like Mr.Hall said, check prices because sometimes youre better off and cheaper to buy a whole carb on the smaller homeowner stuff, say vs a large pro saw, where the carb could be over a 100 dollars, and a rebuild kit 10-15...


just make sure its an adjustable one...

but i feel you, number one thing i deal with is fuel related...primer bulbs, fuel lines and carbs, or adjustments... i bet i have at least 5 or 6 of those very same power heads and a couple extra running engines in my basement right now with no shafts....i started learning how to change port timming on those...

good luck, and if i can be of any assistance, just let me know... i bet i have 20 of those carbs..beleive it or not but a kit wont always fix it either... you'll know its bad if primer bulb doesnt fill the way it should or leaks at all....Stihl stuff honestly should be like 1 maybe 2 pulls on full choke, then burp, then half or kill choke and next pull she goes...thats how i keep all mine...

the walbro carbs they put on their higher end stuff...cost 20% more through Stihl too....

[Shrewcub]

Thanks for all the info mj! I stand corrected. I thought they bought this new, but second guessed myself when I could not find the paperwork in the file cabinet after I posted this morning. My aunt told me she did buy it second hand, so its history is unknown. The saw and blower he did buy new.

The carb will be here Friday. This is the first small engine carb I couldn't fix with a quick cleaning. The 25 year old Echo tree trimmer did bet a bulb and filter last year. The 25 year old log spitter got a fuel pump diaphragm. I'll update Saturday

Sam, did you replace the Welch plugs too?

John, I may figure out exactly what parts it needs and if they don't exceed the price of a new one, try and fix it as a spare. I have a disease that prevents me from throwing stuff out! Except actual garbage.

[Sam Mac]

No I didn't replace the welch plugs.

[mjsoldcub]

hey no problem...trust me you wont want to fix it, dont waste your time $ or resources... it wont make a difference...especially if it was ran with shit gas....like i said i have a literally 20 of them in a bag in my cabinet of "goodies" cuz i dont like to throw shit away either, but trust me, you might get it to start, after like 30 pulls, or maybe even run rich as hell, puking fuel out the exhaust, but it wont be the same as just buying a new carb even a cheap chinese one...i keep mine with fuel in in them all year also, do some high high octane 50/1 mix like in the cans, or i could give you my special recipe


sorry its this way, but Stihl is still the best....

[ambrola]

sorry its this way, but Stihl is still the best....

I have to disagree. I have used Red Max for 20 years and it has never failed to start or work as it should. Same way with the back pack blower. But, as with all things, you get what you pay for. The weed eater was 300.00 way back then? I think it will last me the rest of my life, if I didn't just jinxed myself.

[mjsoldcub]

this isnt a 300 dollar Stihl though, especially way back then....im not just saying that cuz i use em....i have worked on everything from old baird poulans,(the real ones) homies, mculloughs to huskees, to jonsereds, (now just cheap-er huskees) to toros and all in between...some have a higher failure rate and lack of engineering and lesser quality materials...now just thats just my opinion, but like everything stihl is trying to be able to sell things at certain price points that anyone can afford...are they the landscaping 8hrs a day 7 days a week heavy duty built stuff-no...but still a good trimmer, and interchangeable parts from like 5 different models...

anyways....

i miss those old poulans...Shreveport Louisiana they were once made....all the way to the wild thing...thanks again huskee...but if you cant beat em, buy em...and sell them anywhere you can...sorry huskee guys


i used to run a 372xp...it was a good saw actually, except for all the fasteners falling out, the air cleaner cover falling off, and no master switch...but she sure went!!!

[J-Mech]

Echo isn't bad. Better warranty than Stihl, and very similar tools. Plus cheaper. I've had really good luck with the Echo higher end stuff. Just sayin.

Mj, I like the old Homelite stuff. We had Shindaiwa too. Man they were really good!!