Modern Vespa

Ran the engine this morning everthing was ok. Got into 4th and it started to die out on me. It took several tries to start it again. Got it started and rode back to the house. I turned it off and tried to start it again and it wouldn't start. I took a several kicks to even get a "put put" out of it.

Here are the few things I have already checked:

1. Made sure I had fuel
2. Checked the jets - no clogged jets - super clean
3. Checked the float - fuel enters like it should foat goes up like it should
4. Removed the spark plug - examined it and everything ok - even put in a new plug.
5. Loosened the gas cap

After doing all of this, it still loses complete power and just dies and not even at WOT. What on earth can this be?? I've had to call into work this morning and I've spent the last 3 hours or so trying desperatley to fix this problem.

If anyone has any suggestions or has ever experienced anything like this, please offer some advise on what this could possibly be.

Thanks!!

Did you check for spark by removing your spark plug, putting it in your spark plug cap, grounding the little end of it to the engine case, and kicking the kickstart. Do you see the spark arc across the spark plug? That's always one of the first things i check - making sure i have strong, regular spark.

Good man Eric. I'm gonna go outside and give it a try and see what happens. Thanks

How does your plug look? Running rich or lean? Air fuel mix correct?

Alright...we have plenty of spark. This is very cool now I know how to check for constant spark.

The plug looks good. It does have that chocolate brown color so all is good there. What would be my next step? Do you think I'm not getting enough fuel somehow??

Thanks again!

next for me would be :

remove the airbox lid, remove the air filter, hold open the throttle, look down the barrel / venturi of the carb, and verify that when you kick it there's a good amount of gas sputtering downward into the engine.

You know you got spark... that's how i check for fuel. Sometimes, even when i think the float / needle is good on a carb, there's still no gas getting through the carb and into the engine.


Go check that.

Hey - I'm hitching my pony to this thread. My P has a shitty start.
What's this rumor I hear that I should drill a hole in the airbox cover?

Well, drilling a hole in the airbox is going to derestrict the carb a little, affecting the jetting and allowing more air to be pulled in.


Another thing BOTH OF YOU should probably look at is what your compression is ... but that's something you need a compression tester for. ( a special tool - kinda like the one in Gitta's avatar )

Alright. I will go double check to see if fuel is going down the barrel. I'll be back. Thanks Eric.

I really don't see shit coming out of that little brass pipe. I was at WOT and just saw a few speckles of gas go in there. I'm sure gas shouldn't be going in there like a tital wave, but in MOP I didn't see much gas at all go into the barrel.

Clogged up filter on the petcock? I had some debris in my old Puch which would cut off good fuel flow from time to time.

I'd totally pull the carb, strip it apart, and go to your local auto parts store and buy a gallon of chemical carb dip ( comes in a paint can for $20 ). Drop your completely disassembled carb in there... ONLY metal parts... no plastic, no rubber, no cardboard. Only the housings, jets, etc.

Let it sit overnight ... pull the next day, blow out with air compressor, and reassemble.

While you have it apart, note that when you flip the carb upside down pay close attention to that little brass spigot in the venturi where the gas sprays out of. Newer carbs have 1 big hole in the bottom. Older carbs have several smaller holes that can become more readily clogged with mung.

You can run a little wire through those holes and make sure they are free of obstruction.

If the carb and petcock filter check out, check your coil and your condenser. We had a girl in our club that had a similar problem. Turned out to be a coil that was starting to go bad.... that when the engine got up to WOT, the coil would crap out, and her scooter would die. She had to let it cool off before she could start it again. Condensers do this on occassion as well. It baffled everyone because it will still give a spark, just a very weak one, not enough to run the engine.

Thanks guys for the help, I really appreciate it. It looks like I have my work cut out for me.

I had recently sealed my tank with red cote and replaced the fuel tap because it was leaking gas. Once I pulled the tank, I decided to paint my scoot. Maybe some paint got into the tank and the gas may have pealed off some particles of paint in the tank and clogged the tap a little? I'm going to take Eric's advice and pull the carb, take it apart and clean it out. Then I'm going to remove the tank and find a new tank to completely replace it just to be safe. I should have done that in the first place instead of sealing it I guess.

I also had some spark when I touched the kill switch on the head set. I'm wondering if I had fried the ingnition at all? I had it tapped off when I was wet sanding the scoot getting it ready for paint. Maybe some moisture got in there. I need to check the electrical now for sure.

What sucks now is that I have to drive my car...I would much rather ride my Vespa than drive my Audi. 3 years ago I would have NEVER thought about riding a Vespa and leaving my car in the garage.

Creating a spark from the coil by touching the kill switch is possible and won't hurt the ignition. If the points were closed and the ignition switch and kill switch are in the run position, hitting the kill switch will deenergize the circuit collapsing the field and creating a spark from the coil.

Before you start messing with the electrics and changing your tank, take the fuel line off the carb and start her up (stick the end of the pipe in a plastic bottle to catch and petrol / gas ). yop should get a nice steady flow if you do, then you pretty much know that thw problem is with the carb seeing as you dont get much petrol shooting out your venturi.
If you dont get a nice steady flow you can assume you have a problem further up the fuel chain.

BTW i'll drive your Audi if your not useing it

Dont put your bare hands in that stuff. Can cause nerve damage.

Manny