petrol pishing out

[Mickey C]

Hi
my friend has a lovely looking looking 1967 GT that intermittantly has petrol puring out of engine side panel and we're stumped.

the tank seal looks good and no fuel collected in the franme well.

i have changed the seal on the tap above the bowl to eb on safe side and again this looks tight and no fuel leaks even with vigourous shaking.

i have stripped and checked the carb and this looked fine and also replaced the hose.

thought this had sorted it but 10 mins into his next journey huge puddle fo pterol next to him at the lights.

any thoughts or ideas please before my garage, his scooter or us go up in flames please?

[jonny snatchsniffer]

is the banjo washer ok ?

[soullad]

^^^^^^^^^^ what he said ..check for the (normally) red fibre washer

Oh and that the banjo is positioned correctly. Some vepsa carbs had cut-outs so that the banjo could only sit at one angle only. Sit it wrong and it'll never seal. Oh and that the banjo bolt is correct lengthened shanked item, you may simply be just tightening into the thread and not sealing it.

[coaster]

You say you stripped the carb but have you tried checking/changing the float needle? maybe the float bowl is over filling and spilling out of the overflow?

[Mickey C]

thanks very much
2 things to try is more than i had previosuly - i will err on the side of caution and do both - although i think float seemed ok, i will change it.

i will also get another seal for the banjo and Soullad when you say the banjo angle has to be correct - its currently sitting at between 6.00 p.m. and 6.30 p.m. (it if were an hour hand) what 'time' shoudl it say please?

thanks again
Mike

[soullad]

Mickey C
Without knowing exactly what carb you have, best bet is to remove the banjo and then carefully prise out the filter on the carb body. Is there anything obvious in the banjo or carb body that would indicate a one position fit only or are they uniform and can fit together in any 360 degree way and not obstruct the fuel flow?
I hope this is the issue cos its a cheap easy fix.
If the float needle is sticking, I wouldn't have thought that enough fuel would run out for you to notice fuel all over the floor whilst stationary at lights ?
Take the carb top box and filter off and turn the fuel on ... can you see where its leaking from?

[Mickey C]

thansk again Soullad
will try that, problem is that its very intermittant - i will have a look at the banjo but it maybe that he has drive around with panel and carb top and air filter off and wait for it to occur again.
Mike

[coaster]

problem is that its very intermittant -

I hadn't picked up on that, Vespas 'dip' quit a bit when the rider gets on (especially if on the 'robust' side), could it be a leak in the tank which is only submerged at certain suspension deflections? or maybe a cracked petrol pipe flexing with suspension movement?

[Mickey C]

Coaster
now that's a thought i had not had - i have changed the fuel pipe but it does only leak when riding it - he's not the biggest lad but will blame it on his lardy arse and re-do checks with weight on the scooter
thanks very much
Mike

[coaster]

Coaster
now that's a thought i had not had - i have changed the fuel pipe but it does only leak when riding it - he's not the biggest lad but will blame it on his lardy arse and re-do checks with weight on the scooter
thanks very much
Mike

I know how frustrating some faults cane be to pin down I had a T5 that performed fine for a while but then developed a fault every time my 8 stone wife got on the back wherby it would struggle to do more than 25 mph. As soon as she got off it was back to normal She started to get a weight complex This went on for weeks, I checked everything from the fuel tank to the CDI but to no avail. In the end I decided it must be somethig to do with the 28 PHBH that was fitted so bought a standard carb.....that's when I found the problem, the PHBH manifold had been fitted using the original 'shouldered' bolts and the rear one was bottoming out before it griped the manifold. The front one was slightly lose and with 2's up, the pressure from the air filter hose was enough to open a gap and cause a masive air leak. A bit of lateral thinking might have found it sooner