Scoot dies at stop light

[beo111]

Hell Dawgs,

Well I haven't had a problem in a very long time but one has finally come up. After this winter season I had to take the carb out of my 50cc Peace scooter and clean it up in order to get it running. I also adjusted the valves last week to .003 intake and .oo4 exhaust which is the settings I've kept for 4 years. I've had the same gas in there since last season and put Sta-Bil in to hopefully keep the gas fresh. Well I got the scoot running, but when I get to a stop light on the street the bike shuts off or the rpms drop really low to where I have to give it throttle in order for it to not shut off at the stop light. It then goes back to the normal idle. I've never had to mess with the air/fuel mixture screw (it has the brass cap over it so I'd have to break it off) even though I've had the bike for 4 years here in Wisconsin, so I don't want to touch it unless it's necessary. I guess I'm wondering if this is a carb problem, engine problem, or a bad gas problem? I'm gonna drain the gas out tomorrow and clean the carb again, then put in fresh gas. Any help would be great. Thanks.

[richardthescooter1]

I would check that exhaust clamp, make sure its not loose, and also check your intake manifold clamp. What do you have the idle set at?

[beo111]

Thanks for the response! I don't know what the idle is set at because there's no tach on it. I adjust the idle to where the rear wheel is about to turn. I remember this as being the way to do it. Am I right?

[richardthescooter1]

Yes it is. (only if you adjusted the idle after scoot is warmed up)

[lykos23]

My 2009 Peace Sports scooter would occasionally die at stops or when coming down into idle and this was an issue with my airbox being broken. Then the issue persisted with a freeflow filter and the freeflow filter had to be restricted. Now I've upjetted to a 38 idle jet and the dying has stopped with an unrestricted freeflow.

I also can't get the thing to idle properly at all unless the very finicky a/f screw is adjusted properly, it's well worth it to pop the cap off as you should be changing it not only based on the season but based on the particular temperature of any given day (at least I do...)

[beo111]

Ok thanks guys! Do you also think the old gas can be causing this also?

[lykos23]

Ok thanks guys! Do you also think the old gas can be causing this also?
Absolutely. You should always use either fresh gas or Seafoam in the gas tank.

[beo111]

Well today I took the carb out again and cleaned it thoroughly and drained out the old gas and put in fresh gas with seafoam. The problem is that the bike runs but the idle is inconsistent. I was going to adjust the a/f mixture screw and the idle, but while I have the bike on the center stand the idle goes from high rpms to low rpms. It happens by itself which is strange. I'll give it throttle for a second and let go, then the rpms go high for a few seconds then drop low again. Then it goes back up to where the rear wheel spins. Sounds like a carb problem?

[lykos23]

Well today I took the carb out again and cleaned it thoroughly and drained out the old gas and put in fresh gas with seafoam. The problem is that the bike runs but the idle is inconsistent. I was going to adjust the a/f mixture screw and the idle, but while I have the bike on the center stand the idle goes from high rpms to low rpms. It happens by itself which is strange. I'll give it throttle for a second and let go, then the rpms go high for a few seconds then drop low again. Then it goes back up to where the rear wheel spins. Sounds like a carb problem?
Sounds like a carb problem.

Now this happens to me when the idle is really high, but the a/f screw is out of whack, so the scooter tries to idle high but bogs out of it and almost dies. I'm not exactly sure what's going on with your scoot, just talking from experience. :shrug:


By any chance have you cleaned your airbox?

[beo111]

Yes, I took out the entire airbox and cleaned it anyway, even though it wasn't dirty. The filter was clean so I knew that couldn't be the issue. I'm quitting for the day because it's getting late. I think I did everything I was supposed to do except adjust the a/f mixture screw. But with an inconsistent idle I don't see how I can do it.

[lykos23]

Yes, I took out the entire airbox and cleaned it anyway, even though it wasn't dirty. The filter was clean so I knew that couldn't be the issue.
That could be a good thing.

The first time I started figuring out how to solve my own issue with dying at stops was taping the snorkel of my airbox one hole at a time until I had perfect throttle response...

Have you done any plug chops?

[beo111]

Sorry, I've never heard of plug chops.

[lykos23]

Sorry, I've never heard of plug chops.
It just means to take out your sparkplug to check the color of it based on a reference chart.

This wiki http://hondaspree.net/wiki/index.php5?title=Spark_Plugs_and_Plug_Chops has some good info on doing plug chops. However, you may want to do a plug chop while in idle to see if you're getting too much air, because that's all I can think of. :hmm:

[Firehawk989]

Also check your head bolts to make sure they're not loose. Maybe re-check the valve clearances too.

[beo111]

The head bolts are tight and the valve clearance is still correct. I have a spare carb so I think I will throw it in to see what happens. That will let me know if it has been a carb problem all of this time.

[beo111]

Well guys, with all of the symptoms I did narrow it down to the carb. I just decided to purchase a new carb and put it in now it runs like a champ. The idle is smooth and bike feels great on the road. I cleaned the old carb twice and didn't want to put it back in a third time to have it fail. Not sure what went bad on the old carb, but a buddy of mine said he heard that the a lot of people have trouble with small engines because of the ethanol in the gas. I don't know if that's true, but I sure won't put Sta-Bil in my tank anymore. I drained out the old gas and glass filter then put new gas in with Seafoam. I hope all goes well in the future! Thanks for all the help!

[blueboy5000]

I'll bet it's your clutch. When the clutch begins to fail, the first symptom is sporadic idle. This is because the clutch main spring (torque spring) becomes fatigued and does not close properly, causing a lope-ing idle and stalling at stops.

Remove the belt and check the action of the clutch.

[Firehawk989]

Well guys, with all of the symptoms I did narrow it down to the carb. I just decided to purchase a new carb and put it in now it runs like a champ. The idle is smooth and bike feels great on the road. I cleaned the old carb twice and didn't want to put it back in a third time to have it fail. Not sure what went bad on the old carb, but a buddy of mine said he heard that the a lot of people have trouble with small engines because of the ethanol in the gas. I don't know if that's true, but I sure won't put Sta-Bil in my tank anymore. I drained out the old gas and glass filter then put new gas in with Seafoam. I hope all goes well in the future! Thanks for all the help!

Had the same problem with my scoot. I bought it cheap from some guy who had stored it for ~2 years with gas and stabilizer in it. Sta-Bil + cheap low octane ethanol gas + time = carb and gas nastiness. Fortunately mine came to life with a good cleaning, some seafoam, and some ethanol free gas.

Glad you solved it!