Electrical and carburetor problems

[Dennis Cullifer]

So I've got a 80cc motor that I had running fine for the the first couple of days then the carburetor started flooding and I tried to manually fix it but it never worked so I got a new one and when I replaced my carburetor the bike still would not run so I ended up getting a new magneto coil,and sparkplug and I had the bike running again so I thought was in the clear but hours later the carburetor slid back and smoke came out of the area that the carburetor is mounted on for a second then the motor died and I slid the carburetor back on and try choking it but it would not start. Please help I am a noob at this.

 

[sbest]

Hi Dennis,
So many places it could be, where to start?
The engine running well is a good thing. When it stops there is likely only one cause.
You have to find that "root cause".
You are doing "diagnosis by replacement". Valid, but looking for symptoms and root cause is better.

First, what did you change? The carb flooded (gas overflowed?) and you unsuccessfully worked on it.
So you replaced the carb, unsuccessful, so we know that was not the cause of the no start.
New plug and magneto had it running! Only one of those things is the answer. Which one?

Well, the plug is the cheapest/easiest thing to change, so try another new one.
If it starts what have you learned?

Often when we have a problem we replace and adjust so many things we never know where "home" is.
A rule of thumb when problems arise is to return it too the basic "as designed" condition.
We know it runs like that, whereas we never know for sure the results of modifications.
Another rule is to supply what it needs: Fuel, air, compression, spark, timing, exhaust. Have all these?

Fuel? smell gas on the plug? Plug wet? (= too much) Does it pour out of the carb line?
Air? Filter blocked or soaked in dirt or oil? Air leaks (like carb slid off)? Air leaks=too much.
Spark? Check the plug, wet? Dirty? Turn the engine over, bright yellow spark and snap?
Timing is had to check on these engines, but basically is the crank/magneto nut tight or key sheared?
Exhaust, plugged or leaking?

For you Dennis, I'd look closely at your plug. Dirty or wet? Too much gas or oil? Does it spark?
I`d suspect it is dirty and wet with oil, fouled. Replace it and try running 32:1 oil mixture.
Buy a very good quality oil because the cheap stuff will foul plugs, leaving you stranded #!@!!$!!
A quart of $$$ good oil will take you over 600 miles, and save you $3-$6 at a time on plugs.
Pay the extra $3-$6 on better oil.

Steve

 

[Nanonevol]

Make sure you put that carb and intake back on tight.

 

[Dennis Cullifer]

I know it's been a while I've replaced the sparkplug, and I have replaced the coil with a 50/150cc moped coil it ran for five minutes and died so I feel that something is causing these coils to die I'm still on the mystery but so far no luck

 

[sbest]

I guess I write too much.
I suspect it is not your coils failing, but oil fouling from too much low quality oil, or too rich jetting.

I suggest:
1) Drain the gas and switch to a high quality 2stroke oil (Motul or Ipone) mixed at 32:1
2) Install a new NGK B6HS sparkplug, check for spark.
3) Start and run bike up to full speed for about a half mile. Check color of plug insulator as deep as you can see it.

This is what your plug should look like (see the dark band at the bottom):

If you were to cut the threads off (called a plug chop) it would look like this:

Wet, oily, or all black is a sign of too rich or too much oil.

Steve