Idles, but does not run under load

[chadmasterka]

Hey guys, im a new member in this forum but i have used it throughout the process of building my bike.
The engine i am using is a sky hawk 48cc. I have replaced the spark plug and i was wondering if there was any way to fix my problem. Any insight is appreciated

 

[2door]

You need to tell us what you've tried and what you've done so far. In the interim look at these suggestions.

Good fuel flow from tank to carburetor?
Good connections at both ends of the spark plug wire?
Fuel mix ratio?
Spark plug gap?
Throttle cable installed correctly?
Tom

 

[chadmasterka]

So far i've tried putting on a new intake to the carb, checked for air leaks, changed oil from traditional to synthetic, I am using premium gas with 40 ml of 2 stroke racing oil in 4 litres of gas. But the spark plug im using does not fit in the wire unless i screw the thing at the top off. I'm not sure if this is a problem or not. The throttle however is not an issue as it will throttle without problem when idling. I installed a new spark plug yesterday and it started running stronger, will pull very slowl but still bogs out after about 5 seconds

 

[Goat Herder]

So far i've tried putting on a new intake to the carb, checked for air leaks, changed oil from traditional to synthetic, I am using premium gas with 40 ml of 2 stroke racing oil in 4 litres of gas. But the spark plug im using does not fit in the wire unless i screw the thing at the top off. I'm not sure if this is a problem or not. The throttle however is not an issue as it will throttle without problem when idling. I installed a new spark plug yesterday and it started running stronger, will pull very slowl but still bogs out after about 5 seconds

Under a load the atmospheric pressure increases in the cylinder. The more the pressure the more a weakness in the spark path can show up.

I got to play with a spark plug tester when I was in high school years ago in shop class. We had a neat plexiglass box with a mirror in the back ground. We could pressurize this chamber upwards in psi . This in turn one could watch a good plug stay stable or a bad one falter. The more PSI the weaker the spark.

Clean up the wiring and it will prolly work me thinks.

Here are links to how to replace the spark plug wire Replacing the spark plug wire - Google Search

 

[Goat Herder]

Also what is the plug gap? What engine is this?

Welcome to the forum! There are a bunch of friendly folk here that love to help. Just give us enough information to help you!

 

[chadmasterka]

I think the gap is .125 and it is a grubee skyhawk. My dad and i are putting it together