Webcon 151 carbs vs. 31's

[L2Man]

Hi,

I have put some 151's on my big valve engine and its fair to say the running is a bit dramatic.

Ticks over evenly like a swiss watch no fuel loss at carbs as regulator is fitted and running a matched webcon in line fuel pump. Timing set by eye a little advanced.

Ok so you set off from tick over and you get a kangaroo effect between initial throttle and revs climbing and giving it a bootful. Once up around 3000 and thereafter just bl**dy glorious and one of the best twin cams for pulling I have ever had over 30years.

The carbs are new "off the shelf" jetted for twin cam and I will be getting final settings on a rolling road, but some years ago I remember a comment that the progression on webcon's vs weber originals was not good.

It would be nice if a fix is easy to do it before driving off as is as roller is 20 miles away from me and either putting up with the kangaroo effect or driving like a hooligan at my age does not appeal.

Any comments or observations gratefully received. :lol:

 

[Keith Halstead]

Hi,

... before driving off as is as roller is 20 miles away from me and either putting up with the kangaroo effect or driving like a hooligan at my age does not appeal.

:lol:

Brendan - if this does happen, make sure Rod videos it & puts it on youtube - priceless !

 

[L2Man]

Rod' too old to hold anything steady!!!

 

[Rick]

It sounds like the main jets are too big, if you only give it 1/4 to 1/2 throttle does it pull cleanly up to 3000 rpm.

 

[L2Man]

Hi Rick,

Does not like part throttle at all up to 3000,
Only way to get her down the road is to bury
The pedal in the carpet then it pulls ok.
It is running 33mm chokes but can try a smaller
Main and see what the effect is.
The carbs were set up per an autosport article in the
60s for an Iwr elan conversion running big valve
Head and L2's, so could be a bit rich maybe go back to
115s and see if better, it has 105 octane in it so doubt it
Will pink!
What you reckon?

 

[martin k]

you've been using kangaroo petrol

 

[David Baldock]

Hello

I had the head for my Mk1 taken to stage 1A & all parts suppied by Vulcan Engineering in Hanwell, West London many years ago now & it runs very sweetly. Obviously it's happier at higher revs.

It it helps to compere, the settings I have are as follows:

Cams are CP L2's
Inlet valve head dia 1.56
Main venturi: 34
Main jets: 130
Idling jets: 45F9
Accelerator pump jets: 45
Emulsion tubes: F16
Air corrector jets: 180
Anything not mentioned is standard

I use super unleaded with an octane booster

Hope this is of some help

Regards

Dave Baldock

 

[L2Man]

Thanks
will compare with what i have.

 

[Rick]

may not be main jet then, more likely something on the slow running circuit, best to kangaroo to the dyno and get it set up there.