I wrote this in response to a post, but thought it might be worthy of its own post. These are a few things I’ve learned in the past few months dealing with carb issues on 3 ATVs of mine, and 1 of my neighbors. I welcome debate from the guys on here that actually know what they’re doing....
1) The original carb is better than the cheap aftermarket carbs... Since they’re so cheap, I tried replacing the carb to save me the work of a thorough clean and rebuild on one of mine, and my neighbor’s ATV. Worked perfectly on his, worked “OK” on mine. Ran, but not smoothly. Not happy with “OK”, I took my original apart, used some parts from the aftermarket carb that it needed, cleaned it extremely thoroughly (more on this later), and put it back together. Now runs perfectly.
2) Be meticulous (REALLY meticulous) during the cleaning/rebuild process... On the first one I did, I cleaned it with carb cleaner and blew out the passages with air, but didn’t really make sure ALL of the passages and tiny holes were obstruction free. That one ran (again) “OK”, but didn’t have a nice fast idle on full choke, and was a little sluggish. I took it off again, disassembled and did a carb dip, bought a cheap set of progressively smaller sewing needles from Walmart, and made sure ALL of the little holes were obstruction free (some were still clogged even after the dip). Blew everything out, and now that one runs like brand new.
3) Choke (enrichener) adjustment is difficult, but I found the solution.... This may be causing your problem... Getting that 1/8 inch of play in the choke/enrichener circuit is difficult to judge through an old cable, even after it’s oiled. Figured out that one of mine was way off even though it felt right... by measuring. When you have the choke cable out of the carb, use a micrometer to measure from the surface of the choke hole to the surface inside the hole where the plunger bottoms out (most micrometers have a protrusion on the end that will allow you to do this). Transfer that measurement (plus 1/8 of an inch) to the choke cable, measured from surface of the choke nut that contacts the carb to the end of the plunger (not including the nub at the end). If you look at the components involved, my description should make sense. This sets it up perfectly. Then just screw the choke plunger back into the carb, already adjusted. Once it’s set up this way, you can make fine adjustments once it’s in, but you won’t need to.
1) The original carb is better than the cheap aftermarket carbs... Since they’re so cheap, I tried replacing the carb to save me the work of a thorough clean and rebuild on one of mine, and my neighbor’s ATV. Worked perfectly on his, worked “OK” on mine. Ran, but not smoothly. Not happy with “OK”, I took my original apart, used some parts from the aftermarket carb that it needed, cleaned it extremely thoroughly (more on this later), and put it back together. Now runs perfectly.
2) Be meticulous (REALLY meticulous) during the cleaning/rebuild process... On the first one I did, I cleaned it with carb cleaner and blew out the passages with air, but didn’t really make sure ALL of the passages and tiny holes were obstruction free. That one ran (again) “OK”, but didn’t have a nice fast idle on full choke, and was a little sluggish. I took it off again, disassembled and did a carb dip, bought a cheap set of progressively smaller sewing needles from Walmart, and made sure ALL of the little holes were obstruction free (some were still clogged even after the dip). Blew everything out, and now that one runs like brand new.
3) Choke (enrichener) adjustment is difficult, but I found the solution.... This may be causing your problem... Getting that 1/8 inch of play in the choke/enrichener circuit is difficult to judge through an old cable, even after it’s oiled. Figured out that one of mine was way off even though it felt right... by measuring. When you have the choke cable out of the carb, use a micrometer to measure from the surface of the choke hole to the surface inside the hole where the plunger bottoms out (most micrometers have a protrusion on the end that will allow you to do this). Transfer that measurement (plus 1/8 of an inch) to the choke cable, measured from surface of the choke nut that contacts the carb to the end of the plunger (not including the nub at the end). If you look at the components involved, my description should make sense. This sets it up perfectly. Then just screw the choke plunger back into the carb, already adjusted. Once it’s set up this way, you can make fine adjustments once it’s in, but you won’t need to.
