Engine running rich, tried everything twice and no luck!

I guess it could be a weak COIL. everyone always calls the coil a magneto. a common mistake. The MAGneto is the oblong MAGnet that spins inside the COIL. although, a weak coil usually presents as a hard to start engine. if yer engine starts fairly easy, then I would say it's not the coil.
 
It's got me by the short hairs Rudy, the smaller jet SHOULD have done the trick. I've also been working on these little 2 strokes for almost 10 years. Not everyone on this site has the experience but still has the right to TRY to help. It is an open forum. perhaps the powers that be could have a thread for experienced builders only. I dont know how that would work, Just a thought. Personally, I get frustrated with guys that have one build and have all the answers. {have you tried turning the screw in and out} Shows no basic working knowledge of a china girl carb.(Sorry if I hurt yer feelers pulsar) But I guess we all learned one way or another. I know I gave my own share of bad advice when I was a newbie. AND got called on it EVERY TIME. I was building these for several years before I joined this site. AND really didn't know didly about them back then.. If ya dont get butthurt you can learn a lot from the people on this site. I know I did.
fatdaddy.usflg
 
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I know its not a magneto but I also know not everyone knows that. As for weak coil, I've tried swapping them and just a few minutes ago tried a brand new one and a new CDI. Magnet is just as strong as my friends.

Sorry if I sounded irritated this thing is driving me crazy.
 
rudyauction509 said:
I know its not a magneto but I also know not everyone knows that. As for weak coil, I've tried swapping them and just a few minutes ago tried a brand new one and a new CDI. Magnet is just as strong as my friends.

Sorry if I sounded irritated this thing is driving me crazy.
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We're OK bro. I prolly would'a set it on fire by now myself.
fatdaddy.
 
I had one once right out of the box that ran really weakly. Checked cold compression & only had 110lb. It had thin base gasket & fat head gasket, so replaced with fat base & thin head & also noticed when barrel was off, a bit of flashing in one transfer port so cleaned that. Ran reasonably then, but was never a speed demon. Checking barrel while apart, I noticed it was a bit oversized, but not horribly so.

With gaskets changed, it was at 125lb cold compression.
 
rudyauction509 said:
OK I'm going to drill one more small hole and see if that helps. Then I'm going to order an entire replacement motor.
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AND then you will have a good PARTS motor. and when ya take a part off it, and the new motor does the same, you found the original problem. Like I said, I would'a set it on fire a long time ago. But I'm old and grouchy.
fatdaddy.usflg
 
If everything else has been tried, there are only two things left that might do this.
Bad gas?
Poor electrical connection in the CDI wiring?
That's about all I have.
Tough problem you have there.
Best of luck to you! ;)
 
Slogger said:
If everything else has been tried, there are only two things left that might do this.
Bad gas?
Poor electrical connection in the CDI wiring?
That's about all I have.
Tough problem you have there.
Best of luck to you! ;)
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Gas has always been straight from the pump, from multiple gas stations and I've checked, double checked and replaced the CDI and magneto (coil) as well as the spark plug and wire.
 
no 2 motors are alike with these things - if you've gotten it to where is suits you, you're good to go
 
Well it runs fine but getting a steady idle is difficult. Like I said I can live with it now, and when actually riding the plug is nice dark brown so it's not running rich anymore.
 
rudyauction509 said:
I did mention that I've been working with these engines for about 8 years now right? If this was caused by something obvious I'd have figured it out.

I can barely get it to run at all with muffler cap on. 4-stroking at 10mph. so something other than oversized jets is going on. Piston and cylinder have no scratches and no sigh of blow by, compression can lock up rear wheel, remove spark plug and engine spins freely, no change in RPMs when starter fluid is sprayed on bearings, crank case and lower cylinder gasket, head gasket shows no signs of leak, carb now runs extremely lean on my friends engine and still rich on mine.

Tried about 6 different spark plug gaps from .018 to .040 no difference, tried new magneto and CDI, no difference, tried about 4 different spark plugs, no difference, swapped cylinder head with my friends engine, no difference, flushed crank case with carb cleaner and drained completely, no difference, removed choke and air filter and swapped intakes again, no difference.

What am I missing!?! Could port timing do this?

If I turn fuel off, it runs great for about 2 seconds before running out of fuel.
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I have run across engines with poorly made magnets with improper timing that made the engine weak no matter what we tried...
Maybe swap the magnet and see if it helps?
 
maniac57 said:
I have run across engines with poorly made magnets with improper timing that made the engine weak no matter what we tried...
Maybe swap the magnet and see if it helps?
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Worth a try, but I forgot to mention that other than 4-stroking this engine is much more powerful than most of the others I've worked on, it beats my friend's off the line easily every time, but my friend's used to go faster because of the 4-stroking problem. I can still beat him off the line and now our top speeds are almost the same.
 
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