too much fuel stumped

Don Conklin /

my 1982 NU50is gettin way too much fuel and I can't figure out why. I have taken apart and cleaned the carb. I bypassed the choke. I installed a new stator (it was weak anyway). The only time it runs right is when I shut off the fuel and it leans out just before running out of gas. I'm at a loss as to what the problem could be. PLEASE help me.

Re: too much fuel stumped

Could be a heavily plugged exhaust, but its likely your float/float needle.

Make sure the float isn't full of fuel and sinking, take the bowl off the carb and see if the needle is seating and shutting the flow off as the float goes up. Don't fully compress it with your finger, do it lightly as it would normally. If it leaks you found your problem.

Re: too much fuel stumped

Bad Cadillac™ /

Have you rebuilt the carb? If the carb is all stock and rebuilt, there's no reason why it should not run right.

And why did you by-pass the choke? (edited)

Re: too much fuel stumped

Also what exactly did you DO to bypass the choke?

Re: too much fuel stumped

Bad Cadillac™ /

Like Ryan said, your carb is the issue, it's flooding itself. You need a rebuild with new parts.

Re: too much fuel stumped

Don Conklin /
donc OP

Just troubleshooting. I actually have a neighbor working on it for me who works on mopeds due to my work schedule. He's stumped too and we need help. Do you know where I can buy a rebuild kit?

Re: too much fuel stumped

Don Conklin /
donc OP

We just unpluged the hoses and there was no difference in performance. It idles fine but has absolutely no power and smokes to beat hell.

Re: too much fuel stumped

Which hoses, all of them? Did you also cap off the intake port?

Re: too much fuel stumped

Don Conklin /
donc OP

I don't quite know. I watched him pull 2 of the 3 hoses off and start it up. There was no difference in performance it idled fine, smoked to beat hell and bogged down the moment you gave it more gas. we removed the plug and it was black.

Re: too much fuel stumped

Well then you likely fucked up the "bypass". You may be dumping raw fuel in through the auto choke.

Re: too much fuel stumped

Don Conklin /
donc OP

It was acting like that prior to our little troubleshooting excursion. Hence the reason we did what we did. Thanks though.

It had been losing power for the past 2 years and finally got to the point where I had to have it worked on.

Re: too much fuel stumped

Then pull the exhaust and look for carbon buildup at the exhaust port. Put it in a fire for a half hour then bang and flush out the carbon. Also, check your parts as I mentioned in the first place. Until you do one or both of those I don't think continuing to describe the problem is necessary or will further your diagnosis.

Report back.

Re: too much fuel stumped

John Pillinger /

If you rebuild the carb and clean the exhaust, and are still experiencing this problem, try new reeds.

I was stumped for a long time, it turns out if your reeds are just barely functioning the airflow through the carb isn't a straight shot, it will oscillate back and forth through the carb picking up extra gas.

If your carb is shooting out gas without an air filter or if you can hear the air being pushed back out by the piston, this may be the problem.

Re: too much fuel stumped

That would be if the reeds are being held ope nor are broken. The bike would barely run and really only at full throttle if you were lucky to get it started. It wouldn't suck more fuel and smoke more, it'd actually pull less due to the reversion back through the carb. It would make a mess of fuel on the filter though and that could choke the carb. Check it, but it's unlikely.

Re: too much fuel stumped

John Pillinger /

It happened to my bike, it ran and started fine it just always had too much fuel no matter how I adjusted the carb. I'm just suggesting one possibility and how to check for it

Re: too much fuel stumped

Don Conklin /
donc OP

Checked that, No fuel on the air filter. Clean as a whistle. No carbon in the exhaust. Must be the damn carb. Rebuild kits are expensive!!! Damn!!!!!

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