Modern Vespa

I'm having a long standing issue with my ET2; basically I think that I have a carburetor leak. First it was very hard to start, tendency to flood, so I had a shop "service" the carb; it ran once and then when parked it dripped gas very slowly but enough that it was noticeable - smell and a stain on the floor. It wouldn't start at all after that first time.

I had them come back out and after pulling the choke & throttle body they were able to get it to run with a huge plume of white smokey exhaust. Two hours later there was gas beneath it again.

So, I tried it myself, I pulled the carb, completely disassembled it and spray cleaned it with chlorinated carb cleaner, let it dry and reassembled it. It started and ran however 12 hours later there is yet again a small drip of gas beneath it - smaller than before but still there.

My last guess is that when they serviced the carb I realize now that they did not replace the clamp that attaches the carb to the snorkel from the air cleaner and that is the area that is wet with gas and seems to be where its leaking from. From schematics I've seen it appears that there is supposed to be a clamp, it seems they neglected to install one so I didn't either yesterday but will be getting one to try today.

So my questions are -
Is it normal to skip the clamp?
If I put a clamp on it I think there will still be a bit of gas that is in the interior of the snorkel/tube; is that normal?
Any other suggestions? Or is it time to replace the whole carb?

Is it leaking from the carburetor?

The fuel lines on those are notorious for failing.

Did you replace the float needle and fuel tap? It sounds like you were flooding as well.

It doesn't seem to be leaking from the carb itself, The fuel lines are new and I've checked & they seem to be well attached without leaks.

I haven't replaced the fuel tap but the shop who worked on it though it looked good - though I am willing to try replacing it if it keeps flooding.

I didn't replace the float needle, I did clean it thoroughly and the float seems to move freely.

The leak feels as though its around the area where the air intake is hence my thought that the missing clamp may be the culprit though that wouldn't explain the flooding I don't think.

Is there a float needle/rebuild kit available?

If it's coming out near the connection to the airbox, that means the gas level is too high in the carburetor. If the gas level is too high, that means the float needle is bad. If it's happening while the scooter is parked and off, that means the fuel tap is bad too.

We do stock both parts. Give a call if you are interested in purchasing them.

Ok, sounds good, I want to try clamping that intake hose this afternoon and see what effect that has. If that doesn't work out then I'll plan on calling you to order parts to see if that helps. I appreciate your insight!

No problem. The gas should never get up high enough in the carburetor that it could come out the air intake junction. You do need a clamp there to prevent extra air getting into the system. An air leak would cause an erratic idle speed, racing up and dying out. You should have a clamp there to prevent air leaks, but it sounds like a separate problem from the flooding.

Motorsport Scooters... Thank you! Got the parts, installation was a breeze and leak is gone, starts right up, runs more smoothly, essentially everything is back to normal. I wish I'd posted sooner. Thanks again!

Glad you're back on the road.

I thought this fixed it but its leaking again.

For about a week or two after I installed the new float needle and fuel tap everything was fine but then I started to notice that I was having a drip again on the garage floor, not as much as before but dripping just the same. Here's what I had done up to this point:

I tried starting it and it was very resistant and when I did get it to start it ran very rich, lots of white smoky exhaust. I ran it for about a half hour and parked it again, no leak, then two days later the drip was back. I have let it sit again and last night when I pulled the spark plug and used the kickstarter gas basically came gushing out of the cylinder head. Clearly flooded.

I called Scooter West last night and they were helpful, gave me the suggestion to check to see if the fuel tap was working properly; suggesting that if I pulled the fuel line from the carb I should get a little gas out but not much since if the fuel tap is working properly no fuel should be leaving the fuel tank if the engine is off and the vacuum hose is connected.

Well, I pulled the fuel line off the carb and basically fuel came pouring out. Even with the vacuum hose connected I was able to drain the fuel tank through the fuel line while connected to the fuel tap. The guy I spoke with though that was a clear indication that the fuel tap was defective/faulty and that was what was leading to the flooding and the dripping fuel.

I've got yet another fuel tap and fuel line& vacuum line on order and on the way but I am wondering if there are any other suggestions. I'm trying to figure out why the fuel tap failed after less than a month (and 50 miles) and if there is anything else I ought to be checking out. Once again the ET2 sits in the garage waiting to be fixed.

One other question, when I replaced the float needle and cleaned the carb I re-installed the jets I likely over-tightened them (screwed them all the way in), I'm wondering if there is any impact on doing so, when it ran it didn't seem to have an ill effect on performance so I am wondering if this could cause fuel tap/vacuum failures.

Open to suggestions & ideas. Thanks.

I had massive problems with fuel leaking just after I re jetted my carb. I later found that it was the gasket for the bowl on the carb that had caught and had been squashed. You can pick new gaskets sets up for dellorto carbs on eBay for less than £10.

I am having the same exact issue and I did change the gasket on the float reservoir.