Scooter ran fine in march, took it on the highway, 63mph as usual. Then I had power problems, bogging when I gave it full throttle, slow acceleration, low top speed.
Things I've checked or done since problem
gy6 157qmj 150cc (hi tong china scooter)
1) 8 pole stator and flywheel upgrade (works great, checked voltages 120-130v and trigger)
2) engine starts great, idles great
3) I put a thin aluminum plate between the choke and carb, essentially a chock delete(some people JB weld the holes) I tried with and without plate, same problem
4) checked plug (golden brown)
5) New coil (same problem with both)
6) checked all vacuum lines (removal and inspection and pressure test with my mouth)
7) Replaced petcock w/ mikuni fuel pump ( no difference, switched back)
8) Checked fuel filter (clean)
9) Inspected inside of gas tank (no debri)
10) Removed and cleaned carbuerator
11) Check float bowl rubber thing, no tears or anything
12) Put in a 122 jet, stock 104 ( same problem with both)
13) Installed new battery
14) Check all electrical connections at or around engine
15) Tried the stock cdi, no differnce to ncy cdi
16) Inspected intake manifold, installed new gasket and rubber o ring
I am basically on my knees, I need some help.
I am going to replace all fuel lines tomorrow (or whenever the weather permits), and clean the carb again, and switch to the mikuni fuel pump
I know spark is good, I know vacuum lines are good
When I rev up the engine, and it does the bogging thing, its sounds lean ( you know a lean sounding engine) at around 5 or 6k, it kinda sticks there unless i give it full throttle, then i pushes past to 7 but doesn't sound strong.
There must be something lodged in the fuel lines, or I blew my head gasket or something I just have no Idea. Please help me. Thanks
UPDATE: I installed the mikuni Fuel pump, bought new vacuum and fuel lines installed, dissasembled carburetor and cleaned..... Same problem
could it be my valves? did a bust a valve spring and my valves are floating? anybody please help. Thanks
Things I've checked or done since problem
gy6 157qmj 150cc (hi tong china scooter)
1) 8 pole stator and flywheel upgrade (works great, checked voltages 120-130v and trigger)
2) engine starts great, idles great
3) I put a thin aluminum plate between the choke and carb, essentially a chock delete(some people JB weld the holes) I tried with and without plate, same problem
4) checked plug (golden brown)
5) New coil (same problem with both)
6) checked all vacuum lines (removal and inspection and pressure test with my mouth)
7) Replaced petcock w/ mikuni fuel pump ( no difference, switched back)
8) Checked fuel filter (clean)
9) Inspected inside of gas tank (no debri)
10) Removed and cleaned carbuerator
11) Check float bowl rubber thing, no tears or anything
12) Put in a 122 jet, stock 104 ( same problem with both)
13) Installed new battery
14) Check all electrical connections at or around engine
15) Tried the stock cdi, no differnce to ncy cdi
16) Inspected intake manifold, installed new gasket and rubber o ring
I am basically on my knees, I need some help.
I am going to replace all fuel lines tomorrow (or whenever the weather permits), and clean the carb again, and switch to the mikuni fuel pump
I know spark is good, I know vacuum lines are good
When I rev up the engine, and it does the bogging thing, its sounds lean ( you know a lean sounding engine) at around 5 or 6k, it kinda sticks there unless i give it full throttle, then i pushes past to 7 but doesn't sound strong.
There must be something lodged in the fuel lines, or I blew my head gasket or something I just have no Idea. Please help me. Thanks
UPDATE: I installed the mikuni Fuel pump, bought new vacuum and fuel lines installed, dissasembled carburetor and cleaned..... Same problem
could it be my valves? did a bust a valve spring and my valves are floating? anybody please help. Thanks
Last edited:
