Hole in butterfly

[medenview]

Hello All. I recently put my T25 into my local garage for it's annual MOT (she passed) and a little service (TLC purposes). One thing I asked them to look at was poor fuel consumption, it's gone up from around 25mpg to 17mpg. Apart from the fact that I'm using her for short commutes to work most days, I can't think of another reason for this to happen.

Anyway, the mechanic in the garage told me that on looking at the "carb" he noticed that there was a hole drilled in the butterflies and he didn't know why this had been done. I haven't been told by any mechanic that they've done this since I've owned her so can only presume it was done before I bought her.

He wanted to reduce the idle speed, but says that he can't reduce it anymore due to these holes.

Can anyone shed any light on this for me please. (Note: I am not mechanically minded)

Cheers

[gsmoke]

Some carbs are manufactured with holes in the butterfy.
This is to provide air when the van is idling.
What carb is it?
Sometimes a vac pipe can be loose or off, this can cause high tick-over, which cant me reduced by adjusting the carbs. Any air leak could cause this.
Its worth a look and a poke about. You could spray carb cleaner around the manifolds to see if theres any leaks there.
Good luck

[bigherb]

Most carbs have a hole or a small cut out in the edge of the butterfly.

[Plasticman]

Obviously not an all round usefull mechanic if he's never seen a hole in a butterfly before, has he ever worken on an engine with carbs before or is he a fitter ..
mike

[Aidan]

there isn't one in a pierburg 2e3 afaik, drilling a hole in the flap is a bodge to get round a crap idle set up

[kevtherev]

That's correct no holes in a 2e3

[Plasticman]

Lots of carbs dont have them and lots do , OP hasnt said what is fitted to his van ..
mike

[fullsunian]

Are you talking bout the choke flaps or the throttle butterflies

[Plasticman]

OP hasnt said, Hence endless speculation..
Did you get back ok the other night? twas bloody freezing , anyhow nice to have met you, good to put a face to the name
mike

[fullsunian]

OP hasnt said, Hence endless speculation..
Did you get back ok the other night? twas bloody freezing , anyhow nice to have met you, good to put a face to the name
mike

Got back fine mate...but engine men lamp came on in car today, so jumped in the van and the clutch has gone

[Plasticman]

Shyte happens, typical when one lot of wheels is out of use the other goes out in sympathy, hope you know a good mechanic
take care
mike

[silverbullet]

Having just repaired a 2E3 this afternoon for the 1990 velle, both the primary and secondary throttles (underneath) do indeed have a small hole approx. 1.5mm dia in each. Not modified or drilled, it's a production feature.
Same on both the carbs I had to work with. The choke (topside) has a rectangular hole with a light spring flap behind it. It's an emission reduction device, like a poppet valve, that lets extra air in on the overrun.

[Plasticman]

Interesting,Kev's and aidens havent got the hole plot thickens
M

[Aidan]

not mine, it's just a piccie off the web of a 2e3 - it's not a T25 one though, probably a fiesta one, that's why I said afaik as I haven't got a VW one here to check, but Silverbullet has so now we know
Kev's carb was swapped/repaired by Steve at Gasure I think and may be a bitza

[medenview]

Thanks to everyone for replying.

I'm not sure which type of carb is fitted. I'll have a look and compare with my Haynes manual as that shows the Solex 34 and Pierburg 2E3 in the book.

I think the mechanic in question is quite experienced with carb vehicles. I have no reason to doubt his expertise