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Motor running tooooo rich
paslow22 - June 4th, 2016 at 01:39 PM

Hi,
I have just put the 1835 motor in after a rebuild and a repair kit through the 40mm twin kadrons and had the throttle bodies re bushed also set the carb pumps at 5mm, and there was vast amount of black from the exhaust.

Main jet is 130, idle jet is 55

I cleaned the carbs, dried them with the compressor, new gaskets, needle and seats, found one was sticking and changes it. dog bone, shaft, bowl.
Took and the small balls and cleaned it out.
Altered the pump for less pump travel same problem.

Screwed in the air mixture screw until it ran rough then backed it out.
Any ideas please.

Thanks
Darryl

Gracey - June 4th, 2016 at 02:03 PM

What fuel pump and pressure are you running? I know F all about kads but plenty about webers and they're very sensitive to fuel pressure.

Bizarre - June 4th, 2016 at 02:32 PM

I'm guessing it was sucking air through the old leaking bushes.

Now you have had it re-bushed it will be sucking fuel instead.

Is the black at idle or at revs?

jets seem "about right" according to Mr Google - but like above i know SFA about Kads

A blat on a dyno would help

beetleboyjeff - June 4th, 2016 at 04:15 PM

I believe they are very sensitive to fuel pressure - they reckon you really should run a pressure regulator - about 3psi from memory

Bizarre - June 4th, 2016 at 04:25 PM

2 PSI accoring to Mr Google and Mt L Bugget

http://www.lowbugget.com/help_section.html 

psimitar - June 4th, 2016 at 06:24 PM

No more than 3psi for pretty much any carb set up. There's a facet fuel pump specially made for this pressure output and also does away with prone to failure Brazilian VW pumps or chinese ones.

Also need to know what the air jet is as 130 main and 55 sounds good for your engine but if the air is under 160 then will definately run rich above idle. If it soots up doing a test at idle then I'd say high fuel pressure just cause the 55 is a good size.

vw54 - June 4th, 2016 at 11:15 PM

Suggestion THROW the CADS away and get some webbers or Dells

Will be much easier then and cheaper in the long run

HappyDaze - June 5th, 2016 at 06:44 AM

Float levels ?

psimitar - June 5th, 2016 at 06:15 PM

Quote:
Originally posted by vw54
Suggestion THROW the CADS away and get some webbers or Dells

Will be much easier then and cheaper in the long run


What's wrong with Kads? Good flexible carb from a mild 1600 to 1900cc motors. Obviously won't give the performance of a single choke per cylinder but they're far less expensive to buy than IDF's etc and give good fuel economy. Loads of folks in UK and Europe have fitted these with good out the box results.

bugzla - June 6th, 2016 at 06:58 AM

who does dell jets here in oz

Bizarre - June 6th, 2016 at 12:10 PM

Quote:
Originally posted by bugzla
who does dell jets here in oz


What are you after.
I have some jets and vents for sale

psimitar - June 6th, 2016 at 10:17 PM

Quote:
Originally posted by bugzla
who does dell jets here in oz


Look for a rolling road that can tune carbs. They should be able to help.

bevoracing - June 7th, 2016 at 02:38 AM

It might be worth checking if the problem is only on one side. Check the plugs. Perhaps there's only a problem with 1 carb? May have left the washer off the needle & seat or one is faulty. Worth a look.
Tony

vw54 - June 7th, 2016 at 08:24 PM

Interested to know how the tune goes