<HTML>Help please,
my plug keeps fouling on my motobecane Mobelette 50. I have changed the fuel mix,replaced the plug, cleaned the carb. It bogs down on high throttle,
I think it is running to rich. Any advice?
Thank you </HTML>
Running Rich
RE: Running Rich
<HTML>If the sparkplug comes out blackened the mix is too rich. You need to install a smaller jet into the carburettor, and probably replace the airfilter element. A smaller jet allows less feul to mix into the air. The size of the jet is stamped into it but is not always readable.The color of the sparkplug should be coffe-brownish (no milk). Take the feulchamber off the carb, the jet is the coppery screw with that tiny little hole in it right smack in the middle of the carb. If you install a smaller jet the mix will become leaner, with a larger jet the mix will become richer. If the mix is too lean the sparkplug will look light-brownish and might even have burnt electrodes. Be carefull with lean mixtures because a lean mix makes the engine run hotter and that will cause the piston to expand more wich might cause it to get jammed. A lean mix also causes pre-ignition wich can eventually cause the piston to deform completely.</HTML>
RE: Running Rich
<HTML>Thanks for the response, where would I get a different jet? Twenty years ago it ran great with this jet. Has the fuel changed?</HTML>
RE: Running Rich
<HTML>The feul has changed, the sparkplugs have changed, the cylinder has worn, the pistonsprings have worn, the airfilter is probably clogged up and way more.
You really should replace the airfilter if it's been in the moped for more than 2 years or when the moped has run more than 6000 miles.
</HTML>
RE: Running Rich
<HTML>Well I have a newer moped, but I think bogging down is probabluy just a characteristic of a moped, because when mine was stock it did the same thing</HTML>
RE: Running Rich
<HTML>Sorry Rob, stock mopeds aren't calibrated, you have to calibrate it yourself, that's why it bogs down.</HTML>
RE: Running Rich
<HTML>Just take the air filter all the way out and run it for a test before you re-jet it........if the plug turns light brown again and it runs good.......then the problem is a dirty air filter </HTML>
RE: Running Rich
<HTML>Always change the airfilter element every year or every 2000 miles
</HTML>
RE: Running Rich
try a diff. jet
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