No-start, Lean condition: 50cc Scooter -Part 1

To celebrate the end of this non-winter, here is a fun diagnosis on a screamin' 2-wheel machine.

Even on something as simple as this 50cc 2-stroke scooter, there are still many variables that make the diagnosis fun and educational.

No fancy scopes in this video...just some good old fashioned seat-of-the pants troubleshooting :)

Enjoy!

[zfloz]

I'm fiddling this little buzzers since 13 years old, being 38now. They are so much fun. :)) Glad to see you in to them.

[davedraycott]

put the choke solenoid on the bench on white paper mark a line at the end of the needle. connect 12v to it the needle should move either in or out if not it is shot.

[ScottFitzmorris-xh]

Great video! I just learned some stuff I've been thinking about for 20 years. Thank you

[danguy]

The way those auto chokes work is when the bike is cold the choke plunger is fully retracted which is on. when the bike is started the choke is supplied with AC current which then makes the plunger slowly extend out to turn off the choke passage. thats why you didnt get any power to it because otherwise if you left the ignition on for a while a cold bike would be hard to start. The choke would even work unplugged so long as the bike is cold.

[MrSpanishfly]

If you put the filter back on, it will give you the resistance of air you need to maintain the mixture. All these Small bikes mainly run off the magneto, the battery is for starting. Be careful not to run a 2stroke for too long on starting spray, as they need oil in the mix.

[joeleeman]

This is so interesting for a complete novice to watch. Mechanics should really get paid a lot more than they do because without them no one would be able to get to work and make their own paycheck. You made this so newbie friendly and this is something that Ill know how to check on my scooter if it ever presents these symptoms and it might save me a trip to warranty work.

[willemstreutgers]

Ivan, those 2-stroke engines will have starting and running problems after a long stay without using. That is because the lubricating oil will clogg in the carburator and choke, so one have to clean the carburetor for sure. The same counts for the old 2-stroke of my boat. Succes.

[MichaelSmith-swdf]

excellent info I learned about my tao tao 50 scooter! Wish you could come and repair mine, you're great. Found the replacement fuel pump on Amazon! Can't wait to get my machine running again!

[joelmccoin]

Hi Ivan, I am an auctioneer, in the past few years I have sold several of those Asian scooters, none had more than a few hundred miles, none ran, so this one is par for course. Nice to see ya tryin to make this one run, Thanks

[stuzman]

Nice deductive thought process Ivan. I got a little chuckle when you said, "There's something definitely wrong."

[retroguitarmaster]

Nice, i love working on these small systems when i have the opportunity, although they can be tricky sometimes, but overall fun, like putting a small puzzle together

[baxrok.]

Fun to watch and informative as always Ivan. I love that two stroke sound. Watching this reminds me, I've got three carbs to clean. The Hot Rod Minibike carb, trimmer carrb, and mower carb. It's a yearly ritual even though I religiously use StaBil.

[derrenlambert]

I had this on a J range Lambretta, turned out to be a block fuel tank filter situated inside the tank, was hacked up and was blocking the carb repeatedly..

[Reaper]

Those jets in those little carbs plug up like clock work especially with corn fuel . Replace the jets and if the owner is going to let it sit get real gas for it and throw in some Techron . TheReaper!

[benjaminrich]

nice running too lean diagnostic trick with the hand over the carb mouth. :)

[kurrr]

Oh my god this is the answer I think he just said my exact life story at the begging I really hope it’s the same problem

[d.l.mistrot]

Actually the automatic choke doesn't work how you're describing it. It's not really a choke at all. Before you start the scooter an enrichment circuit that allows extra fuel through the carb is open. When u start the scooter the auto choke slowly drops down a needle which eventually plugs the circuit. So if the engine isn't warmed up by riding it before that needle finishes dropping the scooter will die, especially if you don't have an air filter on like yours, the air/fuel ratio will way out of wack

[kleake]

Excellent -- learned a lot-- Parts 1 and 2.. Very well done and explained.

[techtinkerin]

I had a full size car battery in the helmet box, jumping over speed bumps smashed the cold start thing off, I used to just put my thumb over it😊❤️🇬🇧

[johnrobinson]

I see this is vid #1...But i'm going to drop my comment now. Many of these have a vacuum operated fuel pump to fill the carb bowl. Old fuel and varnish may have clogged the ports. It may not be connected/missing. Passages within the carb itself may be plugged with varnish as well. Most have a 3 jet fuel metering system, idle jet, part throttle jet, Main jet. Clean all of them.
Along with ALL the fuel and air passages within the carb body. Replace the fuel pump if it had one. Check the crank case half's for air leaks - if applicable. Reed block to case leaks as well. Replace the choke coil - low buck item. Clean ALL the old gas from the tank, brakleen it. If it has an oil pump to feed pre mix oil -don't use it. Run with oil in the main tank mixed yourself. Set up the idle mixture and it should run like new 1st kick every time. New spark plug will help with

My scoot was given to me. It's 15 years old, sat for years with nasty gas in it. An Italian bike better quality overall than the Asian imports.Went over it top to bottom, it runs like new even with 4k miles on the cylinder 55 + mph after tweeking.