b0rkedCarb
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- Joined
- Oct 24, 2011
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Hi all.
I have an Echo leaf blower, model PB 260L, on which I recently replaced the carb. OE on this guy was a Walbro. It was running rough at higher speeds, and upon taking it apart to try and rebuild, I found corrosion on the inside consistent with what I determined to be corrosion caused by high ethanol fuel. I checked the spark arrester screen and changed the plug before getting to this point, FWIW.
OK, so I found a Chinese-made equivalent carb specifically designed as a replacement for the Walbro. I put it on, but cannot get it adjusted across all RPM ranges. It is running smoothly at low RPMs, but cuts out when I give it gas. I'm not experienced enough to know if the cut out is caused by a mixture too lean or too rich.
But there's one thing that confuses me here. On most every other 2 stroke carb I've messed with, there have been two carb screws to adjust. Once marked "L" for low speed, and the other marked "H" for high speed. I learned how to adjust carbs like this when I was a teenager working for a lawn maintenance company. There's a pretty good time-tested protocol to getting these guys dialed in.
This has one screw near the bottom of the carb, where the fuel line comes in that I figured is for fuel mixture adjustments. There is a second screw of a different size directly on top of the throttle body that is small enough to require the use of a jeweler's screwdriver. I figure this is for the amount of fuel that flows into the carb. I have never seen anything like this before, but I'm just a shade tree mechanic, and don't see a ton of different things as a matter of routine. I tend to learn how to maintain what I own, but don't have much opportunity to branch out.
At any rate, I can't find any combination of adjustments that makes this thing run at higher speeds. Does anyone have a basic outline of what I need to know to get this going? Do carbs of this nature have separate adjustments for high RPMs vs. low RPMs? I'm happy to buy a book if someone has a good reference. I'm only into the carb for US $40 at this point (plus my time of course), but if I can get this thing going again for this price, I'll consider it a DIY win.
It might take me a day or two, but I can post back with pictures and even a video of the motor running if it helps.
I have an Echo leaf blower, model PB 260L, on which I recently replaced the carb. OE on this guy was a Walbro. It was running rough at higher speeds, and upon taking it apart to try and rebuild, I found corrosion on the inside consistent with what I determined to be corrosion caused by high ethanol fuel. I checked the spark arrester screen and changed the plug before getting to this point, FWIW.
OK, so I found a Chinese-made equivalent carb specifically designed as a replacement for the Walbro. I put it on, but cannot get it adjusted across all RPM ranges. It is running smoothly at low RPMs, but cuts out when I give it gas. I'm not experienced enough to know if the cut out is caused by a mixture too lean or too rich.
But there's one thing that confuses me here. On most every other 2 stroke carb I've messed with, there have been two carb screws to adjust. Once marked "L" for low speed, and the other marked "H" for high speed. I learned how to adjust carbs like this when I was a teenager working for a lawn maintenance company. There's a pretty good time-tested protocol to getting these guys dialed in.
This has one screw near the bottom of the carb, where the fuel line comes in that I figured is for fuel mixture adjustments. There is a second screw of a different size directly on top of the throttle body that is small enough to require the use of a jeweler's screwdriver. I figure this is for the amount of fuel that flows into the carb. I have never seen anything like this before, but I'm just a shade tree mechanic, and don't see a ton of different things as a matter of routine. I tend to learn how to maintain what I own, but don't have much opportunity to branch out.
At any rate, I can't find any combination of adjustments that makes this thing run at higher speeds. Does anyone have a basic outline of what I need to know to get this going? Do carbs of this nature have separate adjustments for high RPMs vs. low RPMs? I'm happy to buy a book if someone has a good reference. I'm only into the carb for US $40 at this point (plus my time of course), but if I can get this thing going again for this price, I'll consider it a DIY win.
It might take me a day or two, but I can post back with pictures and even a video of the motor running if it helps.