carb problem

[tommack]

Hi all
I have just serviced my carbs,,put new spindles and discs,new jets And new float valves.
The problem I have is pck won't start unless the jets are fully wound in,,I tried the usual 10 > 12 flats but she won't start
She seems to be over fueling as when the engine stops fuel is coming out of the piston and dripping on the floor .
The only thing I didn't change was the floats as these seemed to be ok.I'm going to order some new ones just as a matter of elimination, my neighbour isn't impressed as it's a bit Smokey too

Tom

[Mahesh]

Did you position you needles correctly, ie with the needle guide flush to the bottom.

Also sounds like spindles are not fully closing.

Mine has a similar problem, (not to your extent) but it's something I've put on hold till I finish with the interior.

[tommack]

[quote="Mahesh"]Did you position you needles correctly, ie with the needle guide flush to the bottom.

Also sounds like spindles are not fully closing.

Thanks for the reply
Yes I did Mahesh I double checked that when I had a read up on faults, it's all a bit baffling. I've even tried turning the jets while its running out of frustration but it just stalls,,,I'll check the spindles tomorrow

[Mahesh]

I had similar, took the carbs off and went through all of the cleaning I done, upon refit they performed differently, I then changed the breather pipes.

Not totally sorted yet, but mentally still taking apart and rebuilding.

Also had the smoke exhaust end, with the fumes.

Daspot oil, breather pipes did help.

[Galileo]

I would have said the float height but they're not that sensitive on an SU, unless of course they are set so high that petrol is coming up onto the bridge, which by your description it may well be doing.

If you haven't already seen it the Burlen guide is useful.

Edit: Poor speeling

[GTS290N]

Have you connected the overflow pipes to the overflow outlet and the supply pipes to the supply inlet?
Not that I know of anyone who would have get them the wrong way round..............

[tommack]

The float height seems ok ill check again tomorrow
And the pipes are on in the correct order

[Jon Tilson]

If you cant start cos its so rich and you have fuel coming out and dropping on the floor past the air valve then your float valves are clearly not working properly.

Read this and try again...

https://dollywiki.co.uk/wiki/SU_Carburetor_Tuning

and float level is CRITICAL to getting an SU running right. Anyone who says otherwise is just wrong....

Jonners

[soe8m]

And using the dolly wiki you will have the carbs for 90% right. For the people who want it 100% right don't adjust the floatlevels by the book and wiki but do it the Dutch way.

Jeroen

[Jon Tilson]

Lol....
We should add your diagrams to the wiki article, which I wrote before your bits were posted on here...

Jonners

[tommack]

Ok update on my carb problem thanks for all the advice given
Mahesh you were right my spindles weren't set right and Jon I went to robsport and bought new floats as I had already got new needles and after a bit of tweaking she fired up with the jets on about 10 flats just need to balance them properly and I think I'm sorted.
So once again thanks for all your input and I think she will have her first run on open roads for about 2 years in a couple of weeks