139qmb scooter bogs down, then won't start for a few minutes By worzx (Read 610 times)

[worzx]

Hello!

I have a problem with my scooter. This occured only 2 times, but I wuold like to investigate and fix it.
So, the problem is that after a few minutes of riding, after stopping, the engine bogs down. It's not something like wrongly set idle speed, because it is properly set, so the engine slows down to idle as it should be, and one or two seconds after it reaches idle and I completely stop, the engine bogs down. This would not really be a big problem, but after this, I cannot start the engine with the starter, neither with the kickstarter. I have to wait a few minutes until it starts up. The first time, I was waiting for about 5 minutes then I could start, the second time, after 2 minutes of waiting I decided to move it home. I was pushing it only for 10 seconds, then I tried to start it, and it started up just as it used to.
I was getting some advices that the problem may be something with the mixture, especially the auto choke. Now, as I know it only helps to get a higher RPM at start to not bog down when it's cold. However, I think if it's completely broken and won't extend the needle, it would only cause constant higher RPMs, but correct me if I'm wrong.
Also, I read that this can be caused by the wrong adjustment of the valves. Does the valves have to be readjusted after some time? The scooter has 1300 kms, and I think if it sohuld be, it won't be this soon. The problem occured above 1000+ kms.

Can anyome help me with this problem?

[jct842]

check valve clearance

[trashtruck12172]

there is really no set time or mileage interval for valve adjustment, just check when engine starts to act up or run poorly.

[Alleyoop]

Yep, the valves are tight and will not hold low rpms because the motor is loosing compression and to keep it running you have to be giving it throttle otherwise it will die when you come to stops.
So it is time to adjust your valves, set both of them to .003 inchs and you will be fine. Here is a video on how to adjust your valves on a 139QMB motor no less.
Alleyoop

[worzx]

Does it cause a random bog down like I have? As I said, it only hapopened twice, the first at summer and the second is a few days ago.

[cyborg]

i would follow Alleys advice and reset the valve lash,,this is the most likely the problem