Cold weather adjustments?

[edog]

Basically, today was the first cold day of the year in my area. I plan to ride all winter if possible (6 min commute to work) but I ran into some problems today, mostly carb related. 

1. Died on me at idle
2. Rough accelerating
3. General issues with acceleration curve and power

Thinking I need to adjust the idle screw at least.. i know density of air etc affects the carb but I wouldn't know how to fix it. I didn't warm it up but maybe I should have.

[CROSSBOLT]

My agility 50 of about 2008 was the most miserable cold weather machine EVER! Just like my 1960 Honda Hawk 250. Not surprised since the only technical difference is the Agility has a bystarter and the Honda had a manual choke. Keep an electric blanky on it at home and at work! Then it will start and run.

[edog]

Well that's good to know i guess... the idle is not steady, its like a sine wave going up and down. adjusted the screw and then it wouldn't start so i put it back where it was. It seems like the fuel air mix screw is much harder to get to. done some internet research and it seems like my symptomology matches a too-lean mix

[CROSSBOLT]

The standard Agility 50 IS way to lean to run properly. Very small main jet. Mine had a #82 and a smooth sleeve (for variator) to derestrict it. The bigger jet made it run better.

[edog]

Can i fix this by adjusting the fuel air mix, or do i need to put a bigger jet on there? would love to not have to take the carb apart. but its just textbook too lean.

[edog]

Well it died on me again today in traffic and I messed with the idle and pilot screws until it seemed to work... It no longer is going crazy with the idle, now it is constant at a pretty low rpm. Pretty sure there is a real carb problem though I haven't a clue how to work carbs.

[CROSSBOLT]

About the only fuel-air mix you can adjust is idle. You can change the main jet for off idle to full throttle fuel-air mix. Also some carbs allow up or down position of the long needle to vary fuel-air.

[edog]

I figure all i need to fix is the idle. It backfires quite a bit and all the problems i've mentioned have been at low speed. At high speed its fine. 

To be clear, i have no experience with engines. I don't know what I need to be looking for as an ideal condition. Any advice on how to get the scooter to an ideal rpm range or mixture is much appreciated

[eamartin]

About the only fuel-air mix you can adjust is idle. You can change the main jet for off idle to full throttle fuel-air mix. Also some carbs allow up or down position of the long needle to vary fuel-air.

Would a larger idle jet be of benefit?

[CROSSBOLT]

Probably not since you can easily arjust the air for idle. Now, the idle jet is SO SMALL it is easily plugged or partially blocked messing up idle. The 50 cc engines are the best mechanic training aid available! Almost no way to destroy them short of running them without oil! Considering how easy lawn mower engines are to run right, the Agility 50 is much more sophisticated and better made so it will respond to sensible adjustments. But you must be pretty fussy about keeping parts clean before reassembly. Also FORCING things to fit just breaks stuff. They are cold blooded like the early Hondas but that can be dealt with. Making the electric choke or by-starter a manual choke is a good step. Making sure the diaphragm is centered and not torn is another. Fiddle with jets and needle position will produce results you can feel.

[edog]

Alright thanks... Time to take apart the carb.
.

[edog]

Well i had actually overfilled the oil back in August in the scooter and looked at the air filter and the little hose that runs under it was covered in oil. It is the little hose you can see in this image: http://www.cyclepedia.com/wp-content/uploads/2014/01/Agility_50_0024.jpg . I see that this is called the puke tube...

Do you think that being overfilled with oil could cause problems like what i've been having? I'm assuming too much oil means it would be even harder to get going when its really cold out.

I was able to fix the idle to get it steady, but it had the same problem in the cold yesterday where it didn't have any power any sometimes the engine felt like it was misfiring or the throttle wasn't doing anything.