The "fuel issue" weekend

[Andres G]

Hi All, long time no read...

It seems that this weekend was not the best in terms of fuel related matters for me...

It all started when I decided to take the wife's 1960 Vespa out for a quick spin on Friday evening, but it died after starting on the second kick. I decided it was too late to mess with it, so I took the SL ('65 - 250 Euro Manual) and the kid for a ride around the neighborhood. When I backed the car into the garage I could smell some fuel, but I immediately chalked it off to the Vespa being flooded so I paid no more attention.

Saturday morning I took the time to completely disassemble the carburetor on the Vespa, took it apart to it's most minuscule expression, put it back together and it still would not start. After attempt number 3 at the disassemble/assemble procedure, I threw the towel. I put the carb into a box, into the trunk of the SL and drove over to a friend of mine who has a parts washer and who agreed to dip it in carb cleaner until I got a needle and gasket kit for it. When I was getting the carb from the trunk, I noticed some fuel seemed to have bled from the hoses coming from the canister on the right hand side of the car... which gave me the afternoon project to tackle.

I drove home to realize I was now looking at a major volume of fuel leaking from a return pipe from the canister that leads to the underside of the car (and that looks like it should have a hose attached to it, but no hose at all    - I'll see if I can upload a picture shortly). I also noticed the canister was making a bubbling/gurgling sound with the engine running. I pulled it and cleaned/blew it off, put it back in place and still see the same issue when the engine is running. By now it was 9 pm and I had not been out of the vapor filled garage for more than a couple hours, so I figured I'd try it on Sunday.

Sunday came around and one thing got ahead of the other. I ended up at the lake on the boat. Great evening, sunny but not too hot, water was perfect for boarding... until the engine vapor-locked. Had to be towed back to the dock 

I thought monday and the new week would give me a break and the SL would not leak gas anymore, so I drove it to work and it was fine when I got there in the AM on colder weather (high 70's). However, this afternoon under much hotter weather (90's) the fuel dripping is back in full blast.

I honestly don't know where to start looking. Any hints?

Thanks in advance,
Andres G

[Paul & Dolly]

Hi Andreas,

I think you have the simple Venting system, if it is fitted on the Right hand side, in which case
Have a look in the Technical Manual here, under Fuel /Fuel Tank/ Fuel Venting System.

I think this may clarify the leakage situation for you, the fix is probably easy.

Good luck

Paul

[Andres G]

Hello Paladin,

Thanks for your response. I'd forgotten about the Tech Manual... great resource, as always.

From the pictures and the read, I gather that I have a combination of issues:
#1 - I need to replace all hoses in the system. They are old and dry.
#2 - Have to put the right clamps on the hoses (although I believe what is there now should be ok).
#3 - The Funny Funnel device is missing entirely... Have to source the part number.

I'll find some time to fiddle with this and will get back with an update.

Thanks for any additional input.

Andres

[Paul & Dolly]

Hi Andreas,

It is also worth checking all 3  metal pipes are clear, they should be easy to blow through, and can sometimes be blocked.

happy motoring
good luck

Paul

[Andres G]

Hello Paladin et al,

I worked on this during the weekend and found what I believe is the single culprit of the issue...

Hoses were fine. I had replaced these when I bought the car about 7 years ago and used internally braided fuel injection hoses... Clamps were firm in place as well. No blockage on any of the three pipes.  However, one of the two small inlets to the tank (the one on the right side of the picture below - from the Tech Manual) is absolutely blocked.



I applied all 125 PSI of air pressure from my home air compressor, but it would not come unblocked. The one on the left side of the pic (it's on the right hand side of the car) allowed airflow into the tank with ease, and flow could be felt placing my hand on the fill hole to the tank. I also put pressure from the fill hole to see if I could drive pressure from the opposite end, but still would not budge.

I was thinking I might try to drive something in there to unblock this passage, but I'm not sure what to use. I did not have anything in my arsenal that was thin enough to go thru yet strong enough to push thru a sturdy blockage.

Has anyone encountered this type of issue? What have you used to unblock?

Thanks,
Andres G

[Paul & Dolly]

Hi Andres,

Good you have eliminated some issues, there should be someone here that can advise, lots and lots has been written here, over the years, concerning most parts of the fuel tank.

It may help to "seach" for gas/fuel tank blockages/problems under "forum" and Tech Manual.

When I was concerned about my 47 year old tank, I bit the bullet and just replaced it last year, costly but, I hope worry free !

Good luck

Paul