New to me QT50 - running rich I believe

Thanh-Danh Ho /

I picked up a QT50 as a project and the previous owner had drilled two 3/8 holes in the exhaust. I found a way to plug the holes and continued to work on getting the moped running. The carb was missing pieces, so I ordered a new one (clone).

I was able to get it running, but I believe that it's running very rich. To get it started, I have to hold the throttle 1/4 open. The Idle adjustment screw is bottomed out and the pilot screw is out 3-4 turns. There is no air filter on it either. I can get it started but it quickly gets very smoky. The carb is new so it should be clean and stock sized.

Additionally, this morning , I un-plugged the 2 holes in the exhaust and the moped ran much better. Still rich, but a lot less smokey. I was going to try to adjust the float, but I'm not sure if that will help.

On a side note, I can unscrew the pilot jet, but I can't get it out of the hole. Not sure if anyone has any tips on that too.

Re: New to me QT50 - running rich I believe

Is the clone the Miniky? Looks just like the Minuki? If so, you probably need to go down on the main jet. I have a thread on here where I received some good advice and part of my issues were that it ran rich and I resolved it by dropping down to a 68 main jet. I have a 60cc top end kit, Miniky clone (from Amazon), oem exhaust and oem air filter/box.

Re: New to me QT50 - running rich I believe

If your idle screw is bottomed out ( meaning screwed all the way in) it should be racing like crazy at idle. I'd look into carb from air cleaner side and see if the throttle barrel is moving at all when you turn the idle screw. And check your jet like Geoff says. although clone carbs don't usually etch a number on the jet. Also make sure your choke cable is moving the choke plunger properly.

Re: New to me QT50 - running rich I believe

Thanh-Danh Ho /

Geoff, Thanks for the reply. I'm not sure who makes the clone but it looks like the OEM and I got it from Amazon. I have some main jets coming in the mail although right now i'm still working on getting it to idle nicely.

Re: New to me QT50 - running rich I believe

Thanh-Danh Ho /

Bob, Thanks for the reply. The throttle barrel does move when I actuate the throttle. The idle adjustment screw is bottomed out but to keep the bike running I have to have the throttle at a 1/4 throw so the barrel isn't even resting on the idle adjustment screw.

Like that it will run steady but fast. Once I try to drop the throttle a little it will die.

Re: New to me QT50 - running rich I believe

Make sure that the cutaway on the slide is facing toward the rear not toward the engine.

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