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Derek
V4 Guru

United Kingdom
1778 Posts

Posted - 11 Jul 2015 :  11:53:56 Show Profile Reply with Quote
Noting the extra details on "the other" forum (they would have been useful here too) you might want to set the float at 10mm and change the idle jet to one a bit bigger. See the full info in the Weber sticky. Note the idle screw details, should be very close to 1 1/2 turns out if the idle jet is correct. Less means too big and more means too small.
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Doive
V4 Fan

United Kingdom
109 Posts

Posted - 18 Jul 2015 :  10:59:20 Show Profile Reply with Quote
Well that settles it. Float was floating, although a little lower than expected. Felt heavy, but no sound of sloshing fuel. Drilled two holes in the top of it, fuel dripped out but less than expected. Put the air line to it, fuel sprayed out the opposite hole. Swapped holes and the float exploded! So that's the end of that, looks like the seam wasn't sealing properly, and the foam inside the float has been filling up gradually. Think the carb is less than a year old! Brass replacement float ordered now.

1973 95 V4 - Toreador Red, Grey Primer and Red Oxide.
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Doive
V4 Fan

United Kingdom
109 Posts

Posted - 26 Jul 2015 :  17:49:32 Show Profile Reply with Quote
Fixed it - I hope! New brass float fitted, with a little modification. Seems the castings were changed slightly at some point, so the brass pivot was too wide for the mount. A spot of bench grinder action sorted it out. Set the float height properly, and it worked. Think the idle jet is too big as it runs best with the idle screw fully in. But now starts with the first crank of the engine and no throttle, whereas before we had to crank for 30-40 seconds. Need a long test drive to prove it.

1973 95 V4 - Toreador Red, Grey Primer and Red Oxide.
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BrianB
Starting Member

United Kingdom
31 Posts

Posted - 10 Aug 2015 :  21:27:07 Show Profile Reply with Quote
quote:
Originally posted by Andyinthegarage
OK, there is loads of great advice out there (and in this post) which I have gratefully used myself, but I tried to tie it all together to give my own experiences and at the same time give a step by step guide to setting up the Weber34 ich - I include it for what it is worth and tho I don't imagine it is the only way...it is One way - hope someone finds it useful - sorry it is rather long:

The Weber 34 ICH is a common direct replacement for FoMoCo carbs, is relatively easy to connect to the throttle linkage, and bar a few pinch points against the servo-vacuum pipe, drops straight in. When correctly adjusted it will give better fuel economy and increased power particularly when combined with an improved exhaust system but if you dive into adjusting stuff without a plan, you can be chasing your tail with no benefits.
So….before you attempt any adjustment:
Make sure your carb has the magic “27” size venture as stamped on the casing – it isn’t impossible to set up a different carb, but 25 won’t give you best performance and 29 is very difficult to get right with most un-tuned engines.
Make sure that your in-line fuel filter is clean, you have adequate clean fuel in the tank and that all electrics are in good order.
Check that the carb is in good condition with the internal filter recently cleaned or replaced. Ideally give it a full service.
Set the timing to standard 6 degrees, and if possible, pre-warm the engine to make starting easier – not hot, just warmed.
After changing anything, replace the air filter before final adjustment of tickover and fuel mix as the type of filter will slightly affect things.
Keep your tools clean to avoid adding dirt to the confusion!
Start settings:
Most agree the standard settings for a 1.5 as being close to those listed below but individual engines, carbs, filters, fuel, altitude, opened manifold passages, exhaust choice etc will all make tuning worthwhile. So, I set up as follows:

Main 155
Idle 55
Emulsion Tube F6
Air Corrector 175
Pump Jet 40

Now, the fun begins….

Start with the idle circuit which takes care of 80% of the performance improvement available and whose fuel is controlled by the Idle Valve.

Back off the tickover adjustment until the screw no longer touches and the throttle plate is closed. Slowly adjust it back until it just touches – watch very closely (smoker's trick is to slip a leaf of hand rolling paper between the surfaces to check clearance)…and then count it in ONE AND A HALF TURNS more. Don’t go beyond this as the throttle plate will clear some very small apertures inside the body and start using a different cycle.
Screw in the mixture screw until it GENTLY grounds and then back out 2 full turns.
Start the engine – it should run, but may sound quite rough, certainly very slow but as long as it is running and not “hunting” it is fine.
If it won’t start, close the throttle tickover screw half a turn just to get it started and remember to open it the same amount once it is running.
Now, by ear, adjust the mixture screw a quarter turn at a time until you find the sweet spot right in the middle between the point where it stops increasing the revs, and the point when it starts to sound a little rough.
Once you have found the best setting, turn off the engine and turn the mixture screw in until it gently grounds again. As you do this, count the turns as this will indicate if you have the right idle valve. Opinions vary (as do engines) but if the sweet spot is between 1 ½ to 2 turns then it is pretty much there. You could try a different idle valve just to see what changes, but otherwise you are fine.
If you count less than 1 ½ then your idle circuit is drawing too much fuel. This is very unusual, so check that your tickover is at 1 ½ turns and repeat the mixture screw adjustment. If you get the same result try a “50” idle valve, but if this doesn’t correct the setting it is unlikely to improve by going further. So strip and clean the carb.
If you count more than 2 turns, you need more fuel in the idle mixture. Go up a size in idle valve (increments of 5). Most engines seem happy in the range 55 – 65.

Repeat your idle mixture screw testing until you are happy, then adjust the tickover to about 850 - 900 rpm with a decent electrical load such as main beam. Replace your air filter, check the settings are unchanged and move on to testing the next circuit and so setting the Main Jet.

Unless you have access to a rolling road, the best test is for the “Kill” method – sounds dramatic. You will need a good long hill, steep enough for you to hold about 1/2 to 3/4 throttle without taking off, with safe places to pull over, no traffic and a spark plug spanner. (That's you, not the hill). Engage free wheel (makes stopping easier). With a warm engine, and fresh or at least clean plugs, set off up the hill on a steady ¾ throttle. After at least half a mile and assuming it is safe to do so, kill the ignition without first changing the throttle, and coast to a halt dropping the car out of gear and releasing the throttle once the engine is dead.
Take out at least two plugs from opposite sides and examine. Oily plugs suggest that the main valve is too big and vice versa for hot dry plugs. Adjust and try again. Again, engines vary, but I have seen preference range from 155 – 185 for a 1.5 engine.

Finally recheck timing hasn’t wandered.

Hopefully by now you have a fairly good setting which you can then gently tweak to get the best average setting for all temperature, load and altitude conditions.

You can also try advancing the ignition a little, but only change one thing at a time!.......Have fun!




OldBart
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BrianB
Starting Member

United Kingdom
31 Posts

Posted - 10 Aug 2015 :  21:30:20 Show Profile Reply with Quote
Many thanks for your help Andy; this really is excellent.

OldBart
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Mos6502
V4 Beginner

USA
90 Posts

Posted - 04 Sep 2016 :  17:11:15 Show Profile Reply with Quote
Simple question: If you're fitting this carb to a 1.7 engine, do you still want the 27mm version? Or will the 29mm version work?
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john-saab
Administrator

United Kingdom
2647 Posts

Posted - 04 Sep 2016 :  18:48:51 Show Profile Reply with Quote
The 29mm can be used on the 1700 (as it can the 1500)but you will have to jet right down to avoid high idle speed. That means you may find a stutter when pulling away. Once up to speed you will benefit but the stop/start may be annoying.

'73 96 (Vernon),'74 95 (Veronica)plus 4 other 95's and 2 96's
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FromTheKeyboard
Starting Member

USA
36 Posts

Posted - 06 Nov 2016 :  19:26:37 Show Profile Reply with Quote
Hello everyone,
I've been looking around online for the correct 34 ICH carb for my 1969 96, and the only mostly-accurate listing I've found is from Eurocarb.com.
Currently, I am living on the West US coast, so I don't know much about the legitimacy or reliability of these European sites.

If someone could tell me if this site is indeed reliable, and if the listing is good, I would truly appreciate it.

Here is their listing for the carb:
https://www.dellorto.co.uk/shop/weber-carburettors-parts/single-carburettors/ich-carburettors/15290-029-weber-34ich-27mm-venturi/
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BrianB
Starting Member

United Kingdom
31 Posts

Posted - 06 Nov 2016 :  20:01:34 Show Profile Reply with Quote
Sorry, no knowledge of Eurocarb, but have dealt with Fast Road Cars in the UK http://www.fastroadcars.co.uk/shop/index.php?act=viewDoc&docId=2.
You could try Jack Ashcraft http://www.subrew.com/jackashcraft/ at least he's on your side of the pond!
All the best.

OldBart
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melle
V4 Guru

United Kingdom
2254 Posts

Posted - 06 Nov 2016 :  20:09:27 Show Profile Visit melle's Homepage Reply with Quote
Nothing wrong with Eurocarb. However, I prefer to buy from Fast Road Cars in Wales, knowledgeable chap and top notch service.

www.saabv4.com
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FromTheKeyboard
Starting Member

USA
36 Posts

Posted - 26 Dec 2016 :  03:53:36 Show Profile Reply with Quote
Hello again everyone,

Well, I finally got the 34 ICH, and here are the stock statistics:

Main Jet: 150 (155 included)
Air Corrector: 175
Emulsion Tube: F6
Idle Jet: 50
Pump Jet: 50
Venturi: 27

Now, going by Andy's instructions back on page 2, I will be needing a size 55-size Idle jet, along with a 40-size Pump jet.
But so far, I haven't been able to find a size-40 Pump jet anywhere, so would a stock 50 work for now?

Additionally, my carb didn't come with a manual or auto choke. Will I need to purchase one of those?
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Andyinthegarage
V4 Fanatic

United Kingdom
357 Posts

Posted - 28 Dec 2016 :  11:47:49 Show Profile Reply with Quote
Hi FTKB,

All the details in my post are illustrations drawn from other sources and my own experiences, so don't break yourself trying to get the exact match - each carb and engine will differ anyway.

Plus, you will be able to change the various jets with the carb in place, so go ahead and fit what you have, then enjoy the process of tweaking!

In any case, the pump jet controls the "squirt" of additional fuel used on initial acceleration to keep the mixture rich enough to cope with the first seconds of demand. Your 50 jet is fine as a starter, though you might find the engine stumbles slightly if you open the throttle suddenly. Chances are that you will only notice this when standing over the engine and operating the throttle by hand as the foot is rarely as fast as the hand. (or is that just in karate films?)

Best source of weber parts is Fast Road Cars - very helpful, and they are pretty cheap items, so if you are placing an order anyway, I suggest you buy a range of main jet sizes so you can experiment.

Regarding the choke question, a little confusing - do you mean that there is no obvious connections to the choke "flap" at the top of the carb...or are you saying there is no flap at all?

If so then I am afraid you probably have a Weber 34 ICT not ICH.

A

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FromTheKeyboard
Starting Member

USA
36 Posts

Posted - 28 Dec 2016 :  21:00:27 Show Profile Reply with Quote
quote:
Originally posted by Andyinthegarage
Hi FTKB,

All the details in my post are illustrations drawn from other sources and my own experiences, so don't break yourself trying to get the exact match - each carb and engine will differ anyway.

Plus, you will be able to change the various jets with the carb in place, so go ahead and fit what you have, then enjoy the process of tweaking!

In any case, the pump jet controls the "squirt" of additional fuel used on initial acceleration to keep the mixture rich enough to cope with the first seconds of demand. Your 50 jet is fine as a starter, though you might find the engine stumbles slightly if you open the throttle suddenly. Chances are that you will only notice this when standing over the engine and operating the throttle by hand as the foot is rarely as fast as the hand. (or is that just in karate films?)

Best source of weber parts is Fast Road Cars - very helpful, and they are pretty cheap items, so if you are placing an order anyway, I suggest you buy a range of main jet sizes so you can experiment.

Regarding the choke question, a little confusing - do you mean that there is no obvious connections to the choke "flap" at the top of the carb...or are you saying there is no flap at all?

If so then I am afraid you probably have a Weber 34 ICT not ICH.

A





Thanks for the help Andy.

Yeah, I worded that choke question badly.
It has the whole choke linkage assembly on the carburetor itself, but it does not include a choke cable. This is why I was wondering if I should purchase one.

Here's a link to the listing on Webcon that I got the carb from:
http://www.webcon.co.uk/shopexd.asp?id=738

I realize that it says this model is for a 1.6L engine, but after looking over the internals of it, I really don't think that matters.

Additionally, here are a couple of pictures of the carburetor I received: http://imgur.com/a/w7egK
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Zagato
V4 Mad

United Kingdom
740 Posts

Posted - 16 Feb 2017 :  18:18:35 Show Profile Reply with Quote
I put a Webber on my last 96 but have forgotten what I did for a later model retaining the plastic air filter.

I had to get different rocker covers off an older model, I think as they had different fixing points for the air filter.

I needed a reducing kind of foam gasket for it to fit the top of the Webber I think!

I think I needed a "manifold" or something for it to fit the top of the engine which were hard to come by.

Does this sound right, any idea re supply of possible said parts and where do I get the Webber from, a guy in Wales sells the genuine ones I think I read! Thanks


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john-saab
Administrator

United Kingdom
2647 Posts

Posted - 24 Feb 2017 :  18:49:15 Show Profile Reply with Quote
The early metal air filter can be adapted and looks a lot better than the plastic housing. You will need to alter the brackets (that attach to the rocker covers) and trim the lower edge as it sits a bit higher on the Weber (it touches the bonnets "hinge beam")

'73 96 (Vernon),'74 95 (Veronica)plus 4 other 95's and 2 96's
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