Hi all

I've got an idle problem that is driving me up the wall.

I've finally narrowed it down to the Dellorto carb.

I have blown the jets out and lifted the top off this carb so many times now I can count the number of turns to remove the top screws!!

However I must be missing something as each time I put it back on the car and start it up - same old problem!

I know for sure that it isn't a manifold leak (or spark) as I've borrowed a friends carb and tested that and we idle beautifully. I was also running it for 6 months previously with no troubles.

The details
Always number 1 cylinder that is not idleing.

1700 type 4
Twin Dellorto 36's
Vent 32
idle 52
main jet 135
airs 180
pump 33
emulsion 9164.2

Any suggestions on something thats often missed when cleaning these carbs??

Thanks
Jeremy

Has to be something inside?
Need to get a compressed air can and blow it out.

I guess you need to blow the chunk out - not further in

Thanks Bizzare

I'm coming to the conclusion it probably is a chunk of something stuck somewhere inside I can't see - and isn't dissolved by carb cleaner...

So I might visit a friend with a compressor and get some decent volume of compressed air into the sucker.

Cheers
Jeremy

yeah blow opposite the direction of flow........did you pull the plug at the bottom of the fuel bowl and clean with the jets and mixture screws removed?

take the large plug off the side of the carb and clean the progression holes too.

Hi

Yes, I pulled all the brass jets and plugs and squirted compressed air from a can through them all. When this made no difference I tried carb cleaner.

The carb cleaner seemed to come out the appropriate hole when it was squirted into one, but I've probably been squirting it further in - not out!

Will try again.

Thanks
Jeremy

yes, they are very small gallery's...........might be time to look for something else if you believe you have them cleaned thoroghly.........can take a copuple of goes but

personally i would pull the WHOLE carb off the car AND apart to be sure

plenty of pics on where to go in my members ride thread........but sounds like you already know.

the dellorto tech book has great tips!

If nothing you've done helps, strip the carby bare and use ultrasonic cleaner.If there is some blockage or obstruction in the galleries, that will shake it out.

Thanks guys

For the moment I have fitted my carb top and all my jets / venturies etc to my friends carb - and it idles perfectly.

So there must be a partial blockage or something in one of the galleries in the main body of the carb somewhere.

Cheers
Jeremy

get a wire bruch and use it to check all the jets to see if there blocked it will be the air idle jet

Hi Dave

The Jets are all okay as they are now in my mates carb that is on the car idleing beautifully.

Question to all - Are the O-rings on the mixture screws as shown in Hellbugged's thread (image below, from Hellbugged's thread)



supposed to be round as in the traditional O-ring or something special, ie flat sides as shown?

Thanks
Jeremy

i carnt remember the dells completely but if they have an O ring and is cut yes then u will have troble as it will by pass and suck EXTRA air and cause eratic idle

i replaced them with round ones from a kit, the are fine either way..........as Dave above has said, they should be in good order to work properly tho

when you turn the mixture screws in (one at a time) completely closed, then out......does the nmotor change song? this is a good way to see if you do have a blocked jet/circuit and which one

Hi Hellbugged

There was no change in the engine noise when screwed in completely or out for number one. All others worked as they should.

I used the "remove the lead from the dissy" to isolate which cylinder wasn't working, but also tried screwing in and out the mixture screws on each barrell to see if that made any difference.

The offending carb is now sitting on my bench completely stripped - would be nice to sort so I can return my mates one!

Thanks for the help guys - the knowledge and help here is fantastic...

And that build of yours Hellbugged is awe-inspiring! (and I havn't gotten past the carb cleanup!).

Cheers
Jeremy

I replaced all the o rings on my mixture screws before Warwick as they were gonsky. normal O rings the right size did the trick as Daimo said.

I stripped my carbs before Warwick and cleaned everything. I even polished a few things too!! Like venturi's and cleaned all the brass jets up till they gleamed!!

So jezza what was the outcome , im interested as i have the same problem.
Cheers

Hi all

Sorry to take so long to respond, I've only just sorted the car out.

To be honest I sorted out the problem in the end by tracking down another set of 36 dells off an Alfa freind, and swapped everything to the "new" body and fitting that and the problem went away.

I was under time pressure so I wasn't keen to fluff around any longer than I already had. Unfortunately the car was sold and I needed to clear it from my garage for the builders (leaky house syndrome - very common problem with early 2000 monolithic clad houses in NZ).

So I'm now VW'less...

... for the moment.

Thanks to all for the help.

Cheers
Jeremy

PS said Alfa freind mentioned that it could well be an air leak around the throttle spindle. He suggested spraying starter spray at the spindle on the offending side to see if the engine idled better - a little hard to test on No.1 cylinder in a VW!

have you replaced all the plugs and try differant spark leads other than that put a new dizzy cap on they do crack and its hard to see
i wait until dark than start it or get someone to start it
and you watch for any wayward spark i did this when i just could not fix in the dark it stood out like a beacon

Jeza,
"Dellorto Drip" could have been the problem?. It's been discussed on TheSamba a few times. You can do an off-the-car test for it.


HTH
Ctefeh