I'm stumped here.Please help!

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wan37

Member
May 29, 2011
354
4
18
Illinois
OK I have a 48cc grubee sky hawk.I have some issues with hard starting now after it dies .It will start again eventually after trying it a couple minute later.but idles for a bit and engine idles down then dies.I tried a cns carb first which it came with,then thought It was the carb so I put a new nt on it does the same thing with Idle.It starts and revs OK at Idle but no mid throttle under load. cuts out and backfires at times.both carbs do the same thing .I'm just thinking bad cdi or magneto(coil) does that sound like it could be a cdi or coil..please help I'm done racking my brain with this.
 
Last edited:

takeitez

New Member
Dec 19, 2011
139
0
0
Clayton Missouri
Did it used to run with the current carb properly? Is the choke lever stuck in a half way position? Maybe the main jet has fallen out and your engine is flooding. Those are the things I would check first. Also maybe give the air filter a good cleaning.
 

wan37

Member
May 29, 2011
354
4
18
Illinois
yes had two different carbs on it,cns and a new nt which both ran the same way at idle and back firing at mid throttle.checked fuel filter in tank and replaced it with a new one . ngk plug new wire new only thing is left is coil or cdi.but give me some more Idea's.
 

takeitez

New Member
Dec 19, 2011
139
0
0
Clayton Missouri
hhm well I could be wrong about this but if it is running at idle chances are it is not the cdi or coil. Just wondering, and I am only sayin this to be thorough, you do have your choke off right? Sounds like you are running real rich. Take off the air filter on the nt and check to make sure the choke is working right.

Hey your not too far from me are ya?
 

wan37

Member
May 29, 2011
354
4
18
Illinois
I'm about 1hr at most from you.I used to work on page off I170.I went shopping at galleria mall buy you.okay back to this post I have tried 2 differents carbs both do the same thing.Thats why I'm stumped.
 

takeitez

New Member
Dec 19, 2011
139
0
0
Clayton Missouri
Yea got me stumped also... maybe it has to do with the ... wow I have no idea. Maybe check out the whole deal and look to see if there is anything else that seems out of place. Leaks, anything really. Hopefully someone else will chime in. Does the choke help when cold starting or do you never use it?
 

wan37

Member
May 29, 2011
354
4
18
Illinois
Yea got me stumped also... maybe it has to do with the ... wow I have no idea. Maybe check out the whole deal and look to see if there is anything else that seems out of place. Leaks, anything really. Hopefully someone else will chime in. Does the choke help when cold starting or do you never use it?
Some times I use the choke to get it started if I haven't started it in a while.I really think its a bad coil but don't know how to test it.I think there's a way but it's probably to difficult for me.
 

takeitez

New Member
Dec 19, 2011
139
0
0
Clayton Missouri
I just asked because it could maybe indicate if the mixture is way off. You can check the coil without tools (sorta) By taking the spark plug out of the head of the engine and then rolling the bike. You will see if you have a good spark. You can also check with a meter. I havn't done this and don't want to tell you the wrong stuff so you should search that up.
 

wan37

Member
May 29, 2011
354
4
18
Illinois
I just asked because it could maybe indicate if the mixture is way off. You can check the coil without tools (sorta) By taking the spark plug out of the head of the engine and then rolling the bike. You will see if you have a good spark. You can also check with a meter. I havn't done this and don't want to tell you the wrong stuff so you should search that up.
I think as the motor starts to run a bit the spark gets weaker from the coil I really not for sure but it sure seems that way.
 

Edd

New Member
Jan 25, 2012
19
0
0
Cypress, TX
If it's running rich, you could try adjusting the float, and because your spark plug is wet, the engine may be running rich. So you've got no mid-range power? Try pulling off the air filter, then start the engine, warm it up, and go for a quick ride. See if you notice something. That's what was wrong on my bike (float setting and air filter, NT Carb). One more thing. I've heard somewhere else on this forum that a bad spark plug may spark when you test it outside the cylinder (visual spark test), but under pressure in the cylinder will deliver weak/no spark. Spark plugs are pretty cheap and the stock one is terrible anyways. Just something to consider...