Modern Vespa

Hi,

I have a 1997 ET4 125cc. A few days ago it was running fine, then I stopped to fill it up with petrol (definitely petrol - not diesel!) and afterwards it wouldn't start again.

When I press the ignition it's making the usual sound (which means the battery is fine), but the engine just isn't catching. I tried changing the spark plug, disconnecting the evaporation hose, leaving it for a couple of days in case the engine was flooded, and even wringing out the air filter. Still no joy.

Anyone know what could be wrong?

Hi Rob, Welcome to MV.

You "changed" your spark plug , but do you have spark mate?

Cheers

Check your carb. It might have wiggled off of the manifold.

Did you try the Kick Start? I had a few problems myself. but it's just making sure that both brakes are fully stopped before it'll start-up. wish i could be more help but i'm just starting to know this baby.

Hi, thanks for the quick responses. Yes, I've checked that I'm getting a spark and also the carb seems to be connected fine to the manifold. I haven't been able to work the kickstart since I bought the thing, so no joy there!

After reading loads of other posts, I think I might have flooded the carbon cannister (?), because the problem only kicked in straight after I refuelled. If this is the case, is there anything I can do about it? Or should disconnecting the evap hose have sorted the problem?

Also, the one thing I haven't checked that everyone seems to recommend is the fuel tap. Do I just trace the fuel line back to find it? And what exactly am I looking for when I check it?

Thanks again!

the fuel tap is underneath the fuel tank. it doesn't actually look like a 'tap', which is kind of confusing.

i've got the Haynes manual for our engine model (which is different from the LEADER engine) - if you want, i can summarize the procedure in the manual for checking the fuel tap. i've never done it but it looks more or less straightforward.

That would be fantastic if you don't mind. Where can I get a Hayne's manual from? Someone told me they're pretty tough to get hold of.

i got mine off ebay for about 9 quid. they come up fairly frequently.

i'm sorting out a bit of work at the moment; as soon as that's done in an hour or so i'll transcribe the section for you.

okay. on my engine, the fuel tap is on the right hand side of the bike (as you're sitting on it), just a few inches above the exhaust, towards the back. you can access it pretty easily by taking off the bottom panel on the side. it's a round flying-saucer looking thing with two hoses sticking out of it.

from the Haynes manual: "The tap is automatic, operated by a vacuum created when the engine is turned over. If it is faulty, it must be replaced - it is a sealed unit for which no individual components are available. The most likely problem is a hole or split in the diaphragm."

to check it, first you need to trace the two hoses back from the tap and figure out which one is the fuel hose, and which one is the vacuum hose. now comes the fun part - again quoting from the manual:

"to check the tap, detach the fuel hose from the carburettor and place the open end in a small container. detach the vacuum hose from the inlet manifold or carburettor, according to model, and apply a vacuum to it (suck on the pipe end ). fuel should flow from the tap and into the container - if it doesn't the diaphragm is probably split.
Before replacing the tap, check that the vacuum hose is securely attached, and that there are no splits or cracks in the hose. if in doubt, attach a spare hose to the vacuum union on the tap and again apply a vacuum. if fuel still does not flow, remove the tap and fit a new one."

good luck!

Thanks - that's really useful! I'll try it this afternoon. Hopefully won't get a mouthful of petrol

You might just want to take care of the evap system first. An easy fix if it turns out to be the cause of your current problem, and worth doing even if it isn't.

Follow this link:

ET/GT/LX: Hard Starting, Rough Idle, or Stalling

Good luck!

Oops. I just re-read your original post and realized you already disconnected the ....

Never mind.

Note to self: Do not reply to posts until after morning coffee.