please help I resantly bought a Dellorto type carby for my 48cc chinese motor and it wont hit full reves it just 4strokes it runs good at low speed it has a mixter screw I thought it was running to rich I have leaned it out as far as I can until it wont run then wond it in till it runs ok down low but it keeps 4stroking flat out and its hard to start cold as it doesnt have a choke PLEASE can some one out there help ps it ran perfect with the stand carby mike29
Carby problem
- Thread starter mick29
- Start date
The motor 4-stroking could be that your fuel mix is too rich. What is your gas to oil mixture? at 32-1, 40-1, 30-1, 28-1 ? You might want to also check your spark plug color and see what color is it, brown (perfect), white (too lean), black (too rich) and also check the spark plug gap at the higher speeds a gap that is too far will not let it spark try closing it a little and see if that helps.
The mixture screw only changes how much fuel the motor gets, if you are still getting a black plug when your screw is far out then you will have to add less oil to your premix.
On a side note my motor achieves a very high rpm band because my intake manifold is very short.
The mixture screw only changes how much fuel the motor gets, if you are still getting a black plug when your screw is far out then you will have to add less oil to your premix.
On a side note my motor achieves a very high rpm band because my intake manifold is very short.
reg454- adding less oil will make a richer mixture fuel to air ratio. It will make the problem of a too rich mixture worse.
mick29-
Are the screws on the carb you have air bleed type or "regular". If they are the air bleed type, they will get richer as you turn them in.
If you are four stroking at WOT and the carb is indeed set as lean as the screws will allow, you will have to re-jet to a smaller size.
Let us know how it goes.
Are the screws on the carb you have air bleed type or "regular". If they are the air bleed type, they will get richer as you turn them in.
If you are four stroking at WOT and the carb is indeed set as lean as the screws will allow, you will have to re-jet to a smaller size.
Let us know how it goes.
