Modern Vespa

Hey all. I just recently got new gaskets for my carb for my p200E because their was an oil leak coming from the mixture screw access hole in the rear of the carb body. I replaced the 3 main larger gaskets and had to get a new CDI because that was not working. I now have spark and can get the bike to start on the 3rd or 4th kick. I also just adjusted the timing with a timing gun and all is well. The throttle slide is adjusted properly and the idle screw is working properly. I'm not sure if the fuel mixture screw is working or not since I cannot get the scooter to start out in first without stalling. But the mixture screw at the back is set to the 1.5 turns out from tight and the idle screw is set properly as well.

The main problem I am having is that the scooter will rev as long as I keep the throttle twisted, it just takes a long time for the scooter to rev. It's acting as if I'm trying to start out in 2nd gear. I slowly let the clutch out, but it won't have enough power to get it to go. It's very odd. And when I am revving it in neutral, it seems like the motor is trying to spin a 20lbs flywheel, like its slowly revving. The throttle cable is not catching at all and the slide, cable and throttle all move very freely. Even if I remove the throttle cable and pull the throttle slide by hand, it still rev's slow.

BTW, when I take the spark plug out to look at the tip, its very wet with what seems like oil. It does smoke quite a bit on start up, but that is normal isn't it?

Please help me!!

Cold start jet stuck open? (choke stuck on).

It sounds to me like it's flooding or your mixture screw is not right.

To adjust the mixture screw, I slowly turn it back and forth until I get the cleanest and highest idle speed. Occasionally blipping the throttle to clear it out.

Did you replace the float needle?

I did not do a carb rebuild. The scooter was running great before I put it away in storage 2 years ago. It has not been run since then. I may just end up rebuilding the carb. It may be something to do with the carb, and rebuilding it may help. I did not change the jets at all. They are what was put in previously before I started fixing it. The choke is not sticking. The cable goes all the way back in, and the little lever goes all the way in on the carb itself.

I would do a carb rebuild with a new float needle and see where that gets you. Make sure to clean the jets while you're in there.

That's a common procedure for a bike that's been sitting.

Also the gas all over your motor is indicative of flooding and needing a new float needle (and gaskets).

Okay. Thanks much. I will do that. It was a hard carb kit to find, but I found it on monstor scooter parts. I'll update when finished. Thanks so much for all the help so far.

We have them too if you need them.

I was just looking on scooterwest website and it said that they were on backorder? Thats why I got it from the other website.

Totally ok. We are just short the 20/20 base gasket which you wouldn't need anyway. We have the rest. Not to worry.

You need to turn the repar mixture screw out, you are too lean on idle.

Without accelerator pumps, opening the slide in lean condition means you will stutter or stall out.

Quarter turns, until you get a steady idle (may need to adjust the idle speed screw) and no hesitation on application of throttle.

Oh... AFTER you clean the carb!

Ok. I have to rebuild the carbs first, and then i'll try it again. The adjustments made no difference when turning in and out and waiting about 10 seconds for the adjustment to take place. The idle screw did help, but it seems like the motor isn't getting enough fuel, so I'm thinking its the needle float sticking. So the rebuild kit should take care of it hopefully. I will also go over the carb with a fine-tooth comb and clean everything.

Thanks for all the help so far...very much appreciated.

Hello again. So I finally got the carb rebuild kit. I rebuilt the carb and replaced the gaskets. The scooter now fires right up first or second kick which is great, but it still has very slow throttle response. It has a rebuilt carb now and a new plug. Timing is correct. Any ideas on what it could be? Each time I take the plug out to inspect it, it seems like it is saturated with oil...could this be causing the slow throttle response. It still seems like there is just no power. It idles fine, but I have to give it full throttle and slowly let the clutch out to get it to even role forward. I may take a video of the scooter running just so I can show what is happening.

Just some quick guesses:

1. Main jet too large. What are the values of the three jets (air corrector, diffuser, main) of the main stack?

2. Still might be a float sticking open - are you getting gas flowing from the top of the carb with the fuel tap open?

3. You sure your CDI is putting out enough spark? Check for orange or yellow spark color in dim lighting.

4. What plug are you using? I generally start with an NGK B8ES. The higher the number the colder it is.

5. Is your bike kitted? Aftermarket exaust, bigger barrel, port work can each in themselves affect jetting dramatically.

Sorry if I repeated anything that has already been said or tried.

Before you get too far into it... You aren't expecting it to run on the gas you had in there from 2 years ago are you? I can assure you it is no longer gasoline. Flush the fuel tank and put fresh fuel in it

The scooter was running fine before I put it into storage about 4 years ago. I rebuilt the carb(cleaned), replaced the plug and gapped it same plug you mentioned, replaced the CDI because it was bad. The carb float and needle are new with the rebuild kit. The jets were never changed from what was in the carb before. It ran great before. I haven't changed the gas yet. I'll try that. I added some year old gas in a gas can in my garage. How do you adjust the needle and float since there are no adjustments on the float or needle. Also, the new needle I have as a spring loaded end where as the old need did not. It was a solid shaft that didn't move.

The old gas may be the culprit being that I was having the same issue before the carb was rebuilt. Also, not sure why, but when I make timing adjustments, The timing doesn't change in respect to the flywheel and magneto. I am just going to set it to what it was previously when it ran. (still have the original markings from when I replaced the wires of the magneto. I had to rewire all of the wiring because the wiring had bare spots all over.

Another question, The fuel tap originally was position so that strait out towards the front of the scooter was off, up was gas on, and down was reserve. After my dad replaced the tap itself on the gas tank, it now is switch....up is off, strait out is one and reserve is down. It works just fine, It's just switched. Is this a known issue if you use a different tap?

I didn't think the factory taps worked any other way but up= off, straight out is normal running and down was reserve.

My current one has not been factory for several years since I would occasionally snap off that lever with my heel when tapping the choke in with my foot.

I also replaced the actual fuel valve attached to the bottom of the gas tank and am not sure if they kept the direction the same but I would think they would.

Here's what I know for my scoot:

If you are looking toward the back of the bike, front of the fuel tap itself with the lever taken off then all the way clockwise is off, middle is normal running and all the way counter-clockwise is reserve.

Your fuel tap lever might just be flipped around opposite of what the factory had.

Before you do anything replace the fuel. Small engines don't run we'll on bad fuel. It doesn't matter what your tap is doing as long admit turns on. Mine is stock and is stamped on the side. Up reserve middle off down on. Won't matter if I'm running it on nastiness.

yea, I do remember that when installing it. Strait across was off. then clockwise and counterclockwise was on or reserve.

If you want to know 100% then unscrew the banjo with the fuel line still attached. If it is truly off no gas will spew forth into the air box. The other two will be run and reserve (complete opposite end of what 'off' is like).

I agree with scootnwinn - drain the gas and use it in your car. Go get fresh gas and try it again.

I think you nailed his problem...

Okay. So I drained the old gas out of the tank, cleaned it out, cleaned the valve, and replaced the old fuel line with new. I also made sure that fuel was flowing freely when I used the valve. Still have the same issue that I was having with the old fuel. I also checked to make sure there was no gas coming out of the injector due to overflowing of the bowl. No leaking into the throttle body. Here is a link to a video that I made to show what the scoot is doing....

Let me know what you think

omg that cloud! too too too rich. lol

I would think two things: jets are wrong or ignition is jacked in the crack.

what jets do you have in the carb? this is a P200 right?

are all your ignition points clean, firm contacts with the wires and sparkplug?

Yep idle circuit is way too rich. Where is the mix screw set? Turn it in clockwise till it revs.

The magneto should be fine. I had to rewire all of the wiring connecting to the magneto because the wiring was terrible. Resoldered all of the contact points on the magneto and all the wiring coming up through the case. All the wiring is correct. The CDI was ruined, so i had to replace it. I did not change the jets from before when it was running. They worked fine before I put it away in storage. I cleaned the carb a second time, so all the jets are clean. Does the spark plug usually have oil on it after shutting it off? There is always oil on the plug when I take it out to inspect it.

The mixture screw is adjusted what factory said...1.5 turns out from closed. Are the mixture screw adjustments noticed immediately, or do you have to let it run for a little every time an adjustment is made?

They work pretty quick. Turn it in 1/8 turns at a time until your bike responds to throttle the factory default is rarely the right setting there is a reason the thing is adjustable you need to lean it out quite a bit. Summer time always needs a leaner setting

ok. I'll try that. Thanks

ok, so I tried playing with the mixture screw. When I checked the position, It was actually almost screwed all the way in. I tried playing with the mixture screw a bit, and it didn't seem to get any better until I revved it higher. Also, I started to note that their was gas starting to puddle at the bottom of the carb housing which was running down the back of the case. Could this be because of the mixture screw itself? I'll take a picture of it and see if it looks okay to you guys. Also, is it normal for gas to spray out of the throttle body when the air filter is off? Even with it on, gas seems to be spraying certain places.

Be very careful about running that without the cylinder shroud. Its meant to direct the air flow to cylinder head from the flywheel fins, without it the air flow goes astray and over heats the cylinder.

ATM, Maybe you could tell us what jets you have in there presently? Did you change any of them out recently? Good Luck.

Is there a way that too much oil is being injected into the cylinder? The smoke is definitely a blue smoke from the exhaust which means burning oil, and its a lot of blue. Also, is it normal for gas to be spitting out of the carb without the carb cover on? Even with the filter on, it still kind of spits. The mixture screw doesn't seem to be doing much.

The jets that are in the carb were never changed from before. When I get a chance, I will check them to let you guys know what size they are just to make sure it isn't the jets.