PA 50 II Idle / Stall


My ped sat in storage for a long time (like 5 years) with the tank drained. Just took it out of storage, filled it with fresh gas/oil and, bang, started right up.

However, it would only idle with the choke on or by high throttle with the choke off.

I dropped the engine and cleaned the carb completely, decarbonized the head and replaced the spark with a brand new one. The exact same problem persists.

Ped started easily and idles great with the choke on, but when the choke is disengaged the RPM increases for about 10 seconds then the engine stalls.

ANY ideas are appreciated.

Be safe, stay cool.


Re: PA 50 II Idle / Stall

my friend has the same problem...

but he's able to ride the moped at around 25MPH...

he just need to always give a little gaz...

samething for you?


Re: PA 50 II Idle / Stall

Riding is not possible because when I give it gas, the choke lever is automatically disengaged meaning that, once stopped, it'll stall. The trouble seems to be with idling.

Re: PA 50 II Idle / Stall

it could be either the rubber between the carb and the cylinder if it has one, or the reed valves are stuck

Re: PA 50 II Idle / Stall

I think the idle circuit is still plugged up. With the choke on the crankcase loads up with fuel and then when you take the choke off you get some air in it which leans out the mixture and makes it run good.

Try cleaning every passage again. Run wires thru every orifice. Take the emulsion tube out and clean it too but pay particular attenion to the idle circuit.

Re: PA 50 II Idle / Stall - SUCCESS!

Okay, after a week of fiddling, I got it.

The gas/idle screw adjustment was removed completely then the screw beneath it was removed. I poured in a little solvent then blew it out cometely with compressed air.

Even though I thought I'd cleaned out the carb completely, I hadn't. I got it idling just fine now.

Thanks to everyone who posted here an elsewhere on this forum.


Re: PA 50 II Idle / Stall - SUCCESS!

Yep, same thing happened to me, I just needed to clean the carb. However, I have a question that's kind of on-topic -- as far as the choke goes, mine doesn't automatically disengage. How is that supposed to happen? On the throttle screw, there's a hook-looking thing that looks like it's supposed to connect with the choke when the choke is on and the throttle is wide open, however, on my ped it doesn't. Is that because the hook is bent? It doesn't look straight, but it doesn't look like it was bent by hand... hard to explain, but does anyone understand what I'm talking about?

Re: PA 50 II Idle / Stall - SUCCESS!

right next to the idle speed screw is a stiff vertical wire.. it is stuck into the top of the carb body...about 1/2 inch tall.. sticks straight up.

When the choke is closed a little indentation on a tab on the choke lever engages this vertical wire. This holds the choke closed.

When the throttle is moved to wide open, the long tab on the throttle mechanism hits the bent-down tab on the choke lever and disengages the choke lever from the vertical wire. The choke lever return spring then opens the choke all the way.

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