lumpenbike
New Member
Hello everyone,
I have a standard Chinese 2-stroke 80/100cc bicycle engine. I recently installed a NIBBI PE19FL carburetor with a tuned air filter and fresh fuel mix (1:45 oil ratio).
The issue:
-The engine cannot hold idle unless I slightly open the throttle.
-At low throttle it hesitates and “four-strokes”.
-At ~50% throttle and up it suddenly runs great.
-When I snap the throttle closed, the engine stalls.
-Sometimes I get backfire through the carb.
-Air screw is ~2.5–3 turns out. Turning it in makes the engine richer and it dies → so idle seems too rich.
-I tried pilot jets #35 and #30, neither makes a meaningful difference.
Do you have any idea what is causing these problems? Is it the setting, the carburetor is too big, or something else?
Thanks in advance.
I have a standard Chinese 2-stroke 80/100cc bicycle engine. I recently installed a NIBBI PE19FL carburetor with a tuned air filter and fresh fuel mix (1:45 oil ratio).
The issue:
-The engine cannot hold idle unless I slightly open the throttle.
-At low throttle it hesitates and “four-strokes”.
-At ~50% throttle and up it suddenly runs great.
-When I snap the throttle closed, the engine stalls.
-Sometimes I get backfire through the carb.
-Air screw is ~2.5–3 turns out. Turning it in makes the engine richer and it dies → so idle seems too rich.
-I tried pilot jets #35 and #30, neither makes a meaningful difference.
Do you have any idea what is causing these problems? Is it the setting, the carburetor is too big, or something else?
Thanks in advance.
