Modern Vespa

...i posted awhile ago about getting n ET 4. well i just got it my house today.
it has been sitting since last winter. i put new gas in it and changed the plug. the battery is charged and cranks... but it just wont start. i'm definitely outa' my element... looking at the carb i see electric sensors and vacuum hoses!?! my '66 vespa aint got any of those!!!

any help at what to do next would be great!!!

Did you check if you get anything at the HT cap? I assume when you say the battery is charged that you just ran a voltometer at the poles, right?

When you say "it won't start" do you hear the starter motor? Hear the bendix gear?

I'm also presuming you didn't try to kick it over, right? Probably not a good idea yet, those tranny cases are weak aluminum and you can totally crack one trying to kick it over...

I won't ask you the stupid questions, like you're holding the brake when you hit the starter, and that your kill switch is on...

Yest +1 check for spark at the plug. If the cap is loose or the HT wire is funky that could be your cause. Otherwise, the ignition coil might be shot. Mine died on me, took a while to figure the situation out. If it is the CDI/Coil then you WILL hear the engine turning over and you will hear the starter. If you don't hear the starter, sounds like you have another problem. But if you do you might not be getting a spark.

on the ET, you actually have to replace the coil and the ht lead at the same damned time. Exactly like a femsatronic unit on a small frame - the HT is like, glued in to the coil and you'll screw up your coil if you try to pull it out by force.

d'oh.

CDI, uh... let's hope it's not the CDI

Pull out the carb, clean it, re-install..........hot battery and BAM you get a great running ET4.

Congats !!

SDG

OK... thanks for everything so far...

if i spray some starter fluid into the carb(after removal of air in-take tube) it turns over and runs but only on the starting fluid... like the gas isn't getting into the carb. i checked the vacuum pump and it works and the fuel line is clear to the carb... so i was thinking it's a "carb issue".

removal and cleaning the carb is the next step... i was thinking there might be an issue i was over looking before a carb rebuild...?
anything that typically shits-out in the carb that i should look for?
anything electrical that i need to know?
anything at all?

well?

You clean it out good?

you clean out the CV membrane accidentally with carb cleaner?

you stick it back in and now wonder if it's the vacuum pump?

a, what?
...no,i have not "clean it out good" ...and no, i did not accidentally clean CV membrane with carb cleaner ...and no, i didn't "stick it back in" ...i haven't taken it off yet ...and yes i still wonder if it's a vacuum pump or anything else!!!

i really don't understand this reply? i asked for help. is this a lame attempt at humor?

like i said i've never worked on a modern vespa...this is all new to me and i was asking for help... is this the kind of "help" i should expect?

Ok so you ARE getting spark. That's good (cheaper than a new CDI).

Did you check if the fuel tap is opening? It could be that even with a working vacuum pump the line to the tap is loose or cracked, or that the tap itself is somehow not opening. They do get gummed up over time (often they don't CLOSE fully, but I could see it working the other way too). I'd pull the gas line from the tap (be prepared for some gas coming out if instead of not opening it is not closing fully like I mentioned). If no gas comes out when it is off, that's good. Then start the engine using your starter fluid. Does gas start to come out? If not, we've found our problem. If it does, I'd say yeah, it's probably something to do with the carb itself.

Hope that helps!

now that does help... and so far that is exactly what it does. fuel tap open... fuel line is new and has a good flow the engine runs only on "starter fluid" so it must be something in the carb...

OK, now. is there i need to check or "make sure i do ..." before removal of carb? from the smartass(at least thats how it sounded)reply from before; should i not use carb-cleaner on certain components inside of the carb?

Clean the carb and the airfilter.It should run fine.The carbs gum up just like your 2 stroke does. It's not that bad to take it off. ETs are pretty reliable once running. Keep us informed.

Tom:

Step 1 - chill
Step 2 - You seem to have identified that it is an issue of fuel into the combustion chamber. That's a good start. Now the question is where is the fuel supply being adversely effected, and that's going to be somewhere between the inside of the tank and the output of the carb jets.

In principle, other than the vacuum operated fuel tap, you will be dealing with the same basic components as a vintage 2T.

I would troubleshoot as follows:

- - Test the fuel tap and fuel/vacuum lines.
- - - - Remove fuel line from carb and crank engine. You should get fuel flow. If you do, the problem is in the carb.
- - - - If you don't get fuel in above, then remove the vacuum line from the carb and apply vacuum to that line. If you get fuel flow, then the problem is in the carb's vacuum circuit.
- - - - - - If you don't get fuel, then check both the fuel and vacuum lines for problems. Fuel line for blockage, vacuum line for blockage or leak. If both check out OK, then there is a problem in the fuel tap.

If all of the above turns out OK, then you need to check out and repair the carb.

Hope that helps.

Al

No, I'm asking questions because I'm curious where you've gotten, you seemed excited to tear it down.

Man, you vintage guys, so sensitive.

not so much as sensitive as perplexed!?! vacuum hoses!?! electric wires plugged into the carb!?! aaaaaaaaahhh. give me simply 24/24 any day!!! and since the 2T is so easy we do kinda' jump in and tear it apart to find a problem...

but... after removal of fuel line from carb, when i cranked the engine very little gas "dribbled" out of the line, but after it was done cranking the fuel flowed freely for about a second or so..? vacuum pump? or carb's vacuum circuit?

Tom, think of it this way.
Vacuum from your engine cranking opens the fuel tap, gas goes to float bowl. That would be the vac line from the intake manifold to fuel tap.
Vacuum from the engine running opens lifts the carb slide open. That would be the vac line from the intake manifold to the CV membrane. Those hoses must be in perfect condition.
sound like a float bowl clean out is in order. The cv membrane is a rubber boot that gets sucked in on it self lifting the slide. I don't know how vulnerable it is too carb cleaner.
You probably need to be opening the throttle some to start it too.
si24s' rule for simplicitys sake for sure.

Then do a search for removing evap system. There is such a thing as a bad carb on these things. I think it was the cv part of the carb would wear out and couldn't be replaced on the earlier ones. Just clean out the floatbowl and jets first. It's probly gonna work.

*in a red neck drawl- yep. 'preachy-ate-it! ...sticky float was my thought(and hope) too.

Rather than a manual fuel tap, your scoot has a vacuum actuated tap. Carb creates a vacuum when the engine is turning, and that vacuum is transmitted to the fuel tap at the tank and opens it. This is also used on modern 2T engines.

You now need to isolate why fuel didn't flow freely while cranking. Disconnect the the vacuum line from the carb with the fuel line disconnected from the carb, and draw a vacuum on the vacuum line. You should be able to do this by simply sucking on it. If the fuel doesn't flow, take the gas cap off and try again. If the fuel flows, you have a vent problem, although I doubt this because ambient pressure would give you a reasonable initial flow. But it's such an easy step, do it anyway.

When you suck on the vacuum line, it should feel like sucking on a capped tube. If there is constant air flow, the line is leaking or the tap has a vacuum leak. It's really a simple system. If manually drawing a vacuum works and you get fuel flow, then the problem is in the carb. I don't know enough about that carb to help. Of course, the vacuum line could have been poorly sealed at the carb. Check that.

If manual vacuum doesn't get fuel flowing, then you have either a clogged vacuum line, a clogged fuel line or a clogged/bad fuel tap. Check them now.

It's really a simple system. The electrical connection at the carb is most likely the automatic choke. Again, no big deal, and probably not your problem.

Al

super thanks Al! thats the stuff i like to hear. getting ready to test those lines mow! thanks again.

My pleasure. Keep us posted.

Al

I OZ's defense..
He his a cool guy and pretty knowledgeable..(spelling sorry)
Just trying to help like the rest of us...

Oz, never did ask if GF liked sea shell picture.. Send PM..

I'm right there with ya.

Seriously, I was dropping my engine this weekend and as we disconnected a hose, we saw a sudden explosion of coolant from the carb. This was very vexing. I couldn't imagine, based off of the simpler carbs I'm far more used to like on my 90, why there was coolant in there, but... oh well.

Anyway, Aviator's advice is perfect, and couldn't be stated any better. Next step is fuel flow, which is going to be comin' from the vacuum system / hoses.

oops. sorry for not posting anything new... got busy with work. i'll get back with a progress report ASAP...

...sorry for not posting for a while. having major problems with the ET. the guy i got it from rode all winter long last year... snow/rain/ice... and the undercarriage and anything that could get salt encrusted... got salt encrusted... those of you who live in winter locations know what this does to a car... it's worse for a scooter!!! the carb. is about rusted useless... and what a shock i had to find out that my "italian" vespa has a "japanese" carb.? lots of little things need to be replaced(like every freaken' hose!). so it's taken a little longer than i thought it would...

...but slowly but surely getting things "fixed". i hope to be running by this weekend.

wish me luck!