Dellorto DHLA 45s problem with idle , pump leakage

[anthonyfca]

I will add a short video of the problem -  basically it's dribbling in to the carbs (front pair only) during idle so making the Carbtune readings all over the place.

I am in the middle of measuring the petrol depth having just found and read in the thread very near here. 

Anthony

ok file is over 4.89mb so here's my link to it instead: 

the video is much clearer than the static image, and shows all 4 , two dry, two dribbling

https://www.dropbox.com/scl/fo/yhn1zmjrtktsnunldjel3/h?rlkey=1qdt9yi4bjus9qcendw4z06rj&dl=0

and a pic of the problem

[anthonyfca]

where's the edit button?!

I need to change the dropbox link to this:

https://www.dropbox.com/scl/fi/j3udx9y75x3a30hh1mvbh/IMG_7969.mov?rlkey=brscmfg6nzjdvwugqobtxkcyj&dl=0

so it shows only ted desired video file and not a bunch of other stuff as well (not confidential but distracting 

[anthonyfca]

SO I fettled the floats and the problem improved slightly. Meanwhile the accelerator jets do not seem to be working at all and we have a misfire at 5,000 (max 7,000). However, the carbs are all balanced nicely, aside from I wonder if she revs as freely as before

[RedRooster]

Have you checked your fuel pressure? 

[Hamish]

Try some this guys Weber videos

he helped me with the jet dribble !!

he has a Weber video “playlist” that helps with the searching 

Edited October 13, 2023 by Hamish

[Nick Jones]

Hi Anthony,

Carbs are not my specialty but after watching your video clip I think the others have nailed it

Float height, fuel pressure and I’ll just throw in the possibility that the needle valve on the front carb is maybe worn and leaking a bit, which could give the impression of either of the other suggestions.

Nice steady idle!

Accelerator pumps are a whole new game.setting these up is a bit of a dark art, but first inspect the diaphragms and make sure the check valves are working.  If it picks up cleanly when the throttle is opened even now it suggests either that it’s pretty rich or thst there is enough pump action.

[anthonyfca]

thanks, lovely ! Also I found this bit of guidance from a copy of a page from the Dellorto Tech book I think; I am dreading having to remove my carbs, never done it before but access is practically impossible.

 

[anthonyfca]

On 10/12/2023 at 9:55 PM, RedRooster said:

Have you checked your fuel pressure? 

My car builder told me it's ok. Come to that I don't know how to check it. 

[anthonyfca]

On 10/13/2023 at 4:25 PM, Nick Jones said:

Nice steady idle!

That's reassuring thanks (I'm a novice at this)

[anthonyfca]

Hamish thanks - these will keep me busy for a while! At 20:37 where he talks about burn rates, strikes me the Gunson Colortune will/would allow us to see (literally) how to get it right. - anthony

[Hamish]

There is a lot of experience here and on YouTube about these carbs. I have come to the conclusion webers are quite aggressive all or nothing flat out style of carbs. Happiest wide open. 
but Steve’s videos helped me from drips and flames to safe good running. 
partly sorted with misab spring fitting. 

to 

Nice road running. 

 

to winning

I’d suggest carrying a fire stick just in case. 
 

https://www.tr-registershop.co.uk/firesafetystick-10398-p.asp