5 replies to this topic

[johnR]

I've finally found the correct ratio of mixture and advance to make my car go well, but the idle speed is a little high. The adjuster isn't even touching the choke quadrant so I can't lower it that way. When I was 'Vizarding the throttle spindle I noticed a small hole drilled through the butterfly - is it necessary? (HS4) - would soldering it up lower the revs?

[robert.hedges]

Yes. Also if you've fitted new spindle bushes check the flow past they need an extra tap once you've refitted the throttle disc

[Chris1275gt]

I've finally found the correct ratio of mixture and advance to make my car go well, but the idle speed is a little high. The adjuster isn't even touching the choke quadrant so I can't lower it that way. When I was 'Vizarding the throttle spindle I noticed a small hole drilled through the butterfly - is it necessary? (HS4) - would soldering it up lower the revs?

This was the advice given to me by Moke on my HS4~

It's there to reduce NOX on the over-run.

Solder it up.

So I just changed the butterfly to a plain one and cured my problem and has worked fine since.

[sonscar]

If you have had the butterfly out is it the right way around as they are slightly tapered,also they take a bit of centerings causing them to bind.If not ignore this.Steve..

[johnR]

Thanks all, will solder it up.

[83mini1000special.90]

i have the same problem with my idle.its always too high when warm.

 

i thought the small hole is for air on idling?

 

there is another type with a valve in the butterfly. i had this before and changed out for the butterfly with just the small hole