Engine idles great but when gassed it bogs and tries to die. Figured it was a carb issue, but the problem persisted over all mix screw settings. While doing research I learned what a bystarter is and that I haven't wired it in, which I assume means the carb is running rich/choked.. might be the problem?.

Anyway, there are two leads coming from the valve and the wiring on this atv is a mess, it's not evident which wires need to be attached by a connector on the atv's wiring. Basically, I just want to make sure that one is 12v and the other is a ground (I can wire it if this is the case).

thanks!

 

Update-- I just found a diagram and it looks like the 12v/ground scenario is correct. BUT does it matter which one is which. From what I can see they both look the same, is there a way to test which is which with a multimeter?

thanks again

 

Never heard of a bystarter either but an electric choke is powered from the alternator, not the battery, so the heater doesn't warm the choke until the engine is running.

 

What part are you calling a valve?
2 stroke or 4?

 

Thanks for the replies

Two stroke.
As I understand it, the bystarter and its valve (needle) work by heating thermowax to actuate a plunger and needle to close an additional fuel passage. As the motor runs/warms and delivers power to the heater, the wax expands and etc./refer to above. I think they only need 12v ac or dc, and my atv doesn't have a battery (kickstart only), so any 12v lead should work- since power doesn't flow while engine's off
.
However, I'm pretty sure I found the lead for the bystarter and plugged it in- no improvement. Guess it must be something else. The carb is brand new, so it shouldn't be dirty needles. Gas flow seems solid. Running out of ideas here.

http://www3.telus.net/MyScoot/AutoChoke01.jpg

 

I'd see if the exhaust is plugged and do a compression test.

 

Exhaust seems to be flowing freely, pleny of exhaust smoke coming out. Compression should be solid- just installed new piston, rings, head gasket, cyl. gasket, and spark plug.
I can check it tho. What is a good reading on this engine?

 

90 minimum. Fresh I'm thinking it should be 120.
You installed a new piston. Did you have the cylinder honed and measured?

 

Honed, not measured. For as much as I paid for the thing I'm not planning on sinking a huge amount of labor into this thing. I would be surprised if the bore dia is out of spec, the engine seems fairly low mileage

 

If it needed a new piston......