Carb tuning advice

[Oh.go.on.then]

Morning all, can anyone help me out.

I've just installed my new 1776. I wanted to keep it reasonably stock looking so planned to keep the pict 3 off my 1600 with an oil bath air filter. Trouble was when I took the old one off it was a brosol 30/31.

I bought a second hand but almost new euromax pict 3 which reports say should be alright for an aftermarket carb. I jetted it 55idle and 132.5 main, it also has 70 air correction.

The engine started and revved cleanly but wouldn't idle even with the "big screw" (forget what it's called) wound right out!? Anyone know why that might be? Looks like the PO has had a few issues with it as although it looks new you can see all the screws have been tinkered with.

I've put back in my brosol 30/31 with the same jets and it will idle at approx 850rpm but no more. But the "big screw" (must check its proper name) wound almost fully out. Why would the screw need to be fully out?

Trouble is it's a bit disappointing now I have driven it. I know this carb is too small and I do know that a pict 3 is small but I just want low down torque, economy and standard looks. It doesn't go very well though.

Dizzy is a 009 timed at 30deg at 3000rpm and cam is a c25.

That new weber 32/36 I have is looking more appealing by the minute but I'm sure that would be an even bigger can of worms.

Any help gratefully received.

 

[Trikky2]

The stock carb (and manifold) strangle a stock 1600 engine.

This, coupled with the exhaust and cooling fan, is why beetles and buses had that "unburstable" reputation back in the day. You could drive them flat out all day and they took it because the engine was never near its power limits.

By increasing your engine to 1776 you have added to the demands on an already under sized system. Take a look at a 175 cc engine to see how much more gas flow is needed for instance.

Properly set up twins will give you better mpg provided you drive the vehicle in the same way as before.

There are larger single carbs that would cope better than a stock one but then they wont look stock.

If you did this the inlet manifold would still be a problem and your mpg will be inferior to a twin carb set-up.

 

[Oh.go.on.then]

I know in reality 34 ict's would probably be the best compromise but I haven't got £400 for a set and I don't really want to cut the air filter stand off. Seems a shame when it's lasted 45 years.

I know there are lots of people that run standard carbs on bigger engines and of course it won't make the power higher up in the rev range but I'm cool with that.

I'm just not technical enough to know why the "big screw" (really must go and find its proper name now) is wound right out. I'm trying to work out what that is telling me as it must mean something?

 

[Stevec]

I read something on this in the last few days but can't find where it was, it may have been on samba.com. It said something like if you need to unscrew a jet right out then the jet is too small (I think) and you need a different size?
I've just installed a single empi 32/36 progressive carb on my 1641 and it drives lovely, a lot more power if you need it.

 

[yachty]

It's called the bypass screw. This is THE link for setting your carb and there is loads of other useful info too.

http://www.vw-resource.com/34pict3.html" onclick="window.open(this.href);return false;

If you are running an 009, have you got the vacuum port blocked off on the carb? If not, that's your problem right there. If yes, then check for other airleaks at the manifold. All the troubleshooting info you need is in that link also.

Although your carb will work well with your engine around town, just watch out for the engine leaning out/pinking under heavy load (hills etc) and overheating.

The sooner you get some twins on it, the better

 

[Alex VW Heritage]

Your seriously running the risk of running your engine lean and causing serious damage by under carbing the engine.

anything above 1641cc and i would say twins are a must.