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Hi. I was wondering if you could tell me the correct settings for the carb adjustment screws on a Homelite Yard Smart BC900 string trimmer. There are two screws right next to each other, one is red and one is white. I was unable to find a number that looked like a model number so I will give you all of the numbers that I found on the engine. EM-PS01525, Family- YH2XS.0254RA, UT15172, S/N MB1930172. As of right now the trimmer will only run on full choke and on full throttle, if I let off either one the engine dies and I can't keep it going. Any information will help, thanks.
Answer -
The screws have limiter caps on them allowing limited adjustment. From the factory, without the limiter caps, the screws are GENTLY seated and then turned out 1 1/4 to 1 1/2 turns out for initial adjustment.
The needles are tapered so if they are seated too tight you can permantently damage the carburetor.
Have you tried turning out the adjustment screws?
How old it the trimmer?
Let me know.
Eric
No, I have not touched the screws yet, I think that the guy that gave me the trimmer had messed with the screws a little in his attempt to correct the problem. I do not know for sure, but the trimmer looks to be about five or six years old, it has been kept very clean too.
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Try turning the adjustment needles out. With the limiter caps in place you will only be able to turn the needles an 1/8 to 1/4 turn.
You may also want to remove and clean the muffler and spark arrester. Over time the ports clog with carbon blocking the exhaust gas flow and causing poor performance. You can soak the muffler in solvent or use a propane torch to burn off the carbon deposits.
Let me know if it runs any better.
Eric
I removed the muffler, soaked it in a cleaner and then I burned out the remainder of the carbon with a torch (there was a lot of build up in there). It seemed like there was no improvement. I am thinking that the last thing I can do is to clean out the carb. Do you think that would be a good idea?
AnswerI agree...most likely the problem is in the carb. Do you have an air compressor? Use it to blow out the carb orfices.
The carb is pretty simple, just pay attention to how the gaskets and diaphragms are installed. On the fuel metering side, the side with the inlet needle, the gasket goes on the carb body first, then the diaphragm and finally the cover.
The fuel pump side the diaphragm goes on the carb body first then the gasket and cover.
Let me know if this helps.
Eric
