Modern Vespa

Hi,

I have an Et4 125cc and it has recently started to stall when I stop let's say at traffic lights or park. The Engine just shuts off completely. I just had an LX engine put in my ET4 like a month ago!!! I have to say that I might have overfilled it with petrol but not sure. Evap removed. Worked fine utill yesterday. when I start it, it is fine in the IDLE an runs and runs. ThenI ride, slow down and stop - it dies. Then I start it again and it's fine, then ride, slow down and stop - it dies. Argh!! Any ideas fellas?

p.s. I have set the IDLE a bit faster last month as it was a bit to slow. Can that have something to do with it? I have only increased the RPMS so why would it stop the engine.

Much appreciated

woocash

I have now re-adjusted the idle to slower but it still cut's off at the light's or any stop for that moatter. On my way to work it shut off four times. I can't just sit at the lights with my throttle twisted slightly and holding the brake. It seems not to be doing anything good to my engine. I have noticed some backfiring when I let go of the brake and also it seems it takes longer for the clutch to engage. ARGH! so gutted! can't seem to make this bike run with no fault's. since I bought I only have trouble...
Any ideas? Anyone?

woocash

So was it a brand new engine you put in? Mine was doing that and I replaced the fuel line. That seemed to do the trick. But I recently have to give mine a little gas to start it. I've also been messing with the idle.

the engine was second hand and it came off a totaled LX. funny how it shut's off when I slow down and stop but runs fine if I just start it... I had a new fuel line put in as well....

woocash

Take your battery and have it load tested. I'll bet at idle your volts drop too low and your ignition is shutting down.

-Craig

You shouldn't be lowering the idle. If anything it needs to be raised (yes I know you tried this, I'm just saying you're going the wrong way with it at the moment).

Perhaps you need to try an even higher idle than you had? Perhaps you have a vapor lock forming which starves the engine of gas when the revs come down (and the suction therefore drops).

+1 on testing the battery. Technically it should be able to run fine without a battery, but the presence of a bad battery can divert current.

Thanks for the tip, mate.

I will only be able to check the battery after work tomorrow. I am planning to go to the shop where the engine was fitted and ask them to have a ride. Maybe they will know.. I will also ask them to check the battery on the spot.

woocash

Dude.

I have set the idle higher and it has stopped in 75%. I still get the ocasional engine cut off. But I still can't put my finger on the chocking/backfiring ( more of chocking really). Why does it feel like the bike is being pulled on a rope by someone (what? that's the feeling I get!). Short bursts of power - slow- power - slow and then lift off. But still a bit wonky at low rpms. I will set the idle a bit higher and try again.

well, wish me luck...

woocash

[quote="w00cash666"] ok ok! I was just trying to be helpful and clarify that lowering the idle will probably only make the problem worse.

The weird surges and drops in power happen at idle? Or on take-off when you are rolling the throttle? It sounds almost like clogs are passing through your jets. Have you taken steps to clean the fuel lines and carburettor? And try running it a short way with the fuel cap on loose to see if a vapor lock is starving your engine at idle when the vacuum is low.

[quote="xantufrog"] thanks xantufrog

The carb was cleaned about a month and a half ago. And to be honest it didn't even have to, it was REALLY clean. But I did it anyway. Changed the rollers, belt, new fuel line, tap, oil, oil filter, spark plug. And then the whole engine

Need more pointers on the whole "try running it a short way with the fuel cap on loose to see if a vapor lock is starving your engine at idle when the vacuum is low." thing, please. what's the best (and safest) way to do this?

woocash

Ben havin' the same problems w/my S150 for a few months. Same symptoms stalling at lights, power surges, choking, sputtering, backfiring..... So far I've adjusted Idle, removed evap & have been running w/seafoam. the evap has helped the best but still the problem remains, albeit not as bad.

I'll try the loose gas cap next. My warranty ran out in april & my dealer though still open is out of the vespa business. Amarillo also out of scooter biz but still service (120 mi away). I'm worried mostly that it will lead to greater problems. A guy at Amerivespa said it was running rich but I'm not familar with this & haven't really found a solid answer so far on MV.

I've also noticed that the bike is'nt quick off the line anymore & riding WOT 60mph is almost impossible.

Doesn't apply - you have a fully vented tank, no US evap crap.

I have exact same problem on 1999 ET4 125- replaced battery, spark, HT coil, inlet manifold, fuel tap and lines, carb and jets cleaned, autochoke checked, removed evap and now ran out of stuff to try.
It appears that this, for me at least, is just an insurmountable issue and i should sell up or learn to live with it!

I really don't want to learn to live with it I just had a engine put in afer a disaster fix (my fix). I am stalling at the lights and cagers are not really careful in London. I am going to have the bike looked at this afternoon, but I wanted to fix it my self and save money. Well I hope that there is someone out there that knows what might be the cause of all this. Maybe my ET doesn't like her new hart and rejects it after the transplant

will update later in the evening if I won't find an answer on MV.

woocash

I also had this on my (Leader-engined) ET4. Sometimes fine, sometimes it would die at every set of lights and I had to keep the throttle slightly open when stopped.

It just seemed to be one of its cute little quirks

funny how it never occured before but only after the engine change. Maybe the guys at Scootech have missed something. I have the idle set to high right now (a bit higher and I will have to hold my brakes on) and it sort of works (not everytime but even when I do get it not to shut down when I stop, it stils shuts down when I try to accelerate from a set of lights). Very annoying. No fun rides for me...

woocash

Lots of sympathy here - it's no fun when you can't trust your vehicle and have to worry about it all the time. I hope you or the scooter shop can sort it.

Cheers Alice,

I have to get it sorted before the next DonkeiSkok Adventure so I can tag along

woocash

Have you adjusted the idle mixture as well? Get that right first!

to be honest Jim I haven't. I have not done anythig with it before. It was always running fine. I have only adjusted the idle screw. does it have to be changed after a new engine is fitted?

woocash

If it's the carb that came with the new engine - maybe not, but best to check - if it's the original carb with the new engine, then definitely check the mixture adjustment. However - I'd have expected Scootech to have done this anyway - but often it needs to be re-checked once the engine's done some work.

so still my best chance is to go to Scootech and ask them to check it. After all they have fiited it in. right?

woocash

Ha! Five quid repair and it's good as new. You know that cap that hoes on the spark plug? Well that was broken. Quick fix. Problem gone. Why didn't I check that first? Thanks for all your input guys. I am off for a ride. Lots to learn still.

woocash

Glad to hear it was simple to fix and inexpensive.

Excellent news!

i'm glad it was nothing serious. looking forward to meeting you on our next ride!

thanks Guys,
(stressless)
just glad to be back on the road (stressless) 8)

thnaks Genie,

when is the next ride then??

woocash

And the moral of this story is: Scootech are your fiends.

+1

You are so right Doug! I had to pay a fiver for the cap thingy and the guy just installed it for free I think! He just left what he was doing and fixed my bike on the spot. Well that just shows you that there's nothing better then your local garage...

go Schootech!!

woocash

so the issue came back and this time it can't be the spark plug. although it seemed that it was I have changed it myself again and it didn't help. I still stall when I stop. I might have to go back to schootec but I wont have time this week. shit! what is wrong with my bike?

woocash

So did you set the idle mixture or just assume it was OK? And have the valve clearances been checked?

When I went to Schootec I told them that maybe the mixture screw needs to be reset and they said no. The guy just replaced the cap that goes onto the spark plug, started the bike and said that's it. he replaced the obviously broken part. the bike was o.k. for a day or two and it started again. I have changed the spark plug on Sunday just to be sure. Today was the first go on it. still the same.I have adjusted the idle screw to a bit higher to get rid of the engine cut offs, but it onlly helps a little bit (maybe I am setting it to high? I don't really know what it should sound like). Clearances have not been checked.

woocash

how do you tell if your idle speed is correct?

Pretty much the same thing going on here again. I changed my plug after my ET4 wouldn't start at all. It was carbon crusted from a rich mixture I assume and when I changed it the bike fired right up on the first push of the button. It was idling really rough though. Speeding up and slowing down randomly so I rode it a while and then when it was warm I adjusted the idle screw to where it sounded like a good steady idle. Turned it off and tried to start it the next morning and it wouldn't start without giving it throttle. What is up??? I've seen several people on here who say they always give theirs a bit of throttle to start it but I know that I shouldn't have to do that. I'm going to just foul another plug if I can't get this sorted out. Is it the autochoke, the mixture, or what?

Some possibilities

*Fouled plug from improper mixture
*Vacuum leak from hose to carb
*Float needle is binding or dirty or float is sitting too low and needs adjusting
*Spark plug wire needs replacing
*Battery needs to be replaced

Well, I can eliminate all those except for float needle and improper mixture. I think I finally got the idle set just right. It's starting easily and idling smoothly now but I would like to get to the bottom the mixture thing. That's not something I should mess with not having proper tools, huh?

dude,

I went to Scootech and had my bike looked at again. aparently my issue had to do with electrics on it. the other end of the wire that sits on the spark plug has to connectors that go on that round thingy. the mechanic just fiddled with this when the engine was on. every time he squeezed/moved it oyu could here the engine opicking up revs. he just wire brushed the metal plates the connectors go on and needle clipped the conectors themselves. he then put it back on started the engine and it all came back to life. as I said I don't know if the issue in your case is the same/similar but it all seems to have something to do with the spark plug and its wiring. the connectors are where that liitle flap that gains you access to the spark plug cable is (if you are siiting on your bike and reach down beetween your legs). try that. it might help. my issue is gone for now.

p.s. still haven't learned any terminology regarding the engine, I do apologize for my ignorance...

woocash

Well, my issue might be gone too. I think I finally worked out the idle to where it is smooth. It has been starting on the first push of the button lately and running well. I know the part that you are talking about, though. I had a look at it while I was changing the plug. Glad to hear you are up and running! Enjoy!

cheers mate!

so no more stalling at lights. but what is this? the engine shuts down while doing like 30-45mph? oh yes! so what is it now? I am just going going and then gone. all lights are on but the engine is off. I turn the key to "off" and then to "on" and the engine starts up again. no need to hold the brake-push the starter. and sometimes I have to start it with the brake-starter method again 'cos key turning is not enough. ARGH!

any thoughts?

woocash