Hi everyone,
I have owned this trimmer for about 2 years now. It has had a very easy life. Regular use but only about 20 mins per time. I always let it warm up for a few minutes and use Stihl premium synthetic oil 50:1. It has probably had about 15 hours use in total. It has been a great trimmer until last week. I started it and found that it wouldn't reach WOT. It was running ok though and after a few minutes seemed to come good. A few minutes later it started cutting out at idle. I could not get it to keep idling even after it had cooled down and was restarted using choke. I check plug, spark arrestor, air filter. All good. I took the carby apart and cleaned it. It now runs better but haven't had a chance to give it a good run yet.
This is because I found that the black plastic rotor seems to be binding against the housing. This is now causing it to hang and not return to idle under the tension of the spring like it should. I don't think it was doing this before I cleaned it. I have pulled it off and put it back on several times and taken it apart and cleaned. I can't see that I'm doing anything wrong as it just pushes into the housing and 3 screws hold it in place. I have lubricated around the barrel with 2 stroke oil and put some grease under the rubber cap thinking that I may have removed its lubrication during cleaning. It still seems to catch but only sometimes now. When it catches, if you flick it up vertically with a screwdriver it frees up and flicks back to its base position so it seems to be the bottom of the rotor binding against the bore.
Has anyone experienced this problem?
When looking around the net for info on this carb I found many many threads where people were rubbishing these Zama RB carburetors. I read somewhere that in some markets they were replaced with Walbro carbs.
Are these carbs really that bad?
The rest of the trimmer seems to be very well made.
#2
StarTech
Those that are trashing the carburetors just don't how to repair them. For DIYers they tend to lose the roller inside the barrel opening which is item #2 on the follow IPL. This is a tiny roller.
It also better if you are a DIYer to just replace the carburetor. PN A021003880 (Zama RB_K113). This carburetor does have EPA tamper resistance plugs install which requires a 2.5mm removal tool. These plugs are not even shown in the above diagram but I know they are there.
The single hardest & slowest thing to make on any hand held petrol engine is the carburettor.
So supply of them is always a problem .
Add to that different pollution laws allow the use of cheaper versions in some markets and then some markets demand adjustable jets that are illegal in just about every Western country .
So a long model run will usually show several different carbs
Then there are climate differences.
The saws sold in Alaska need freeze prevention where as the ones in Brazil do not.
Ignorant people see different carbs then rather than thinking about why make up stories to explain this just like you did when you were 3 and believed their were faries in the bottom of the garden who did things you did not understand.
The WWW gives these appapleptics a platform and because it is also easier to accept what some one else said than make your own conclusions , others just accept what they have read as fact ( everything on the web is true isn't it ) so it get repeated again & again till Google decides it is a fact .( because that is how Google works )
#4
StarTech
Actually the Zama RB_K113 is adjustable. Both low and high mixtures. Low is is in the rotary barrel and item 3 is high speed (main) mixture adjustment. It just that there are EPA tamper resistance plugs installed.
The only is that I don't have the adjustment specs at hand for the SRM-222 as the latest Echo carburetor adjustment chart I have is the January 2019. But it should be very close to SRM-225.
Thank you very much for your help. I suspect that I have lost this roller guide and will check this evening. It started raining when I was disassembling on a table at the edge of my garage and had to move everything so it could have easily dropped out. I may end up having to buy a replacement carburetor.
I agree that the web can be a place for venting frustration which does not really help others. I tend to stick to forums like this where people know what they are talking about through experience. The amount of time that some good advice can save someone like me with a young family is very valuable. Thanks again.
If I do buy a replacement carb RB-K113 from Amazon or ebay is it likely that it will have the high and low settings correct or will they need adjustment?
#6
StarTech
To me I always assume that they are only tuned to a will start setting; therefore, I always check the tuning. But a lot trimmers are sold without ever being tuned and they run so so.
All this talk about carburetors, but what about the op's real problem? I don't know the answer, but found it interesting that everyone skipped over his real problem.
This is because I found that the black plastic rotor seems to be binding against the housing. This is now causing it to hang and not return to idle under the tension of the spring like it should.
All this talk about carburetors, but what about the op's real problem? I don't know the answer, but found it interesting that everyone skipped over his real problem.
Didn't skip over his problem. He initially had acceleration problems. After he took it apart it started binding which why I asked if he had lost the ramp roller. Otherwise the carburetor needs a good USC cleaning with soap and water and a carburetor kit installed.
Thanks a lot. I can report that the roller was indeed missing and i eventually found it on the ground. Very small part indeed. I replaced it and it is no longer binding. I did a basic carb clean and the trimmer is now running well again. I took out the brass plug while i was there so i can adjust in future if need be.
