Hi there fellow ATV gurus

I have a 167FMM engine that wont start with the startbutton.

The problem is, that when it cranks it almost halts at TDC, each time it tries to turn over. If I pull the plug out, it turns fine, not really fast, but it turns.

With the plug in
https://drive.google.com/open?id=0B7...FlRNndTMDA1bmc

With the plug out
https://drive.google.com/open?id=0B7...0FtTDdHQURtTEk

I have tried to pull start it with another atv. It started and ran fine after a little carb adjust.

So far I have changed the battery, CDI, carb, flywheel incl clutch, starter, plug, coil and piston and adjusted the valves (0.08mm in/out) like many many times. It still runs fine when pulled to start, but it still wont start on it's own.

I have ruled out all the electrics, valves and carb as it works fine when pull started.

Please advise.

 

The problem is either battery, starter, the wires between these, or the one way clutch. As you have changed starter, one way clutch and battery, unless you have bought a dud, the wires must be at fault. Remove clean the terminals and put back tightly:- both ends of the wire from battery to solenoid, from solenoid to starter, the earth lead from battery to frame and earth to engine. A lot of Chinese stuff uses wires of too small a diameter, I have replaced starter and earth wires with thicker cable to give improved starting.

 

Thank you for your reply.

I forgot to mention, that even when I try to jump it with good and working 20A battery, it's the same. I even tried first at the battery terminals on the ATV, then directly on the starter solenoid, shorting it and at last directly on the starter, all with the same result.

You mention the clutch. I remember when changing it, some of those small "tabs" inside it came lose, and Í had to put them back in place. carefully placing them the right way. Could that be the problem, a faulty clutch?

 

If its got a belt pull the belt off and try to start.. Definitely sounds like the starter is not getting enough voltage to turn under the compression. Or their is something to tight causing it to bind. How does the starer work out of the machine.

 

The starter works fine outside and on another ATV.

 

Was this issue ever resolved? I have the same problem with my atv right now. Have replaced my battery, starter, and starter gears. Not sure what to do next.

 

The CG250 engines used in most Chinese 250 ATVs require lots of current to start, even when in perfect tune. Many of these ATVs scrimp on battery cable size which restricts the current flow to the starter. Copper is expensive. Make sure the connections on the battery solenoid, starter, and ground are clean and your battery is in good shape. I went to larger battery cables on my 10 year old Taotao 250 which helped. Another thing I've seen cause this problem is an aftermarket CDI. The Taotao CG250 engines require a different CDI than other CG250 engines and most if not all aftermarket CDIs have the wrong timing curve even though they are advertised to work with that engine. If you have an aftermarket CDI, replace it with one from Taotao.

 

I will recheck all connections in the morning and possibly run better wiring. Will look into a new cdi box as well if the wiring doesn't solve the issue. Thank you very much for your reply.

 

have you found anything out yet I'm having same issue with my cg250. Help!!!

 

Nicol, I found that the new cables are one of the major problems, they are too thin to coop with the amps these CG250 need to start. Along with the battery, of course, you will need that to be as new, charged to max, and at least 12 Amps. My brand new cable harness melted after a few attempts at starting it, so now I put a double diameter positive cables than the ones I had and they just get a little warm but don't melt