Fuel issues weber carb

Hi, 
My 1.3 with a weber 34ich carb is not running right! 
It is often hard to start when cold, and then needs choke to stay going. On acceleration, it would sound as if she is missing, which is helped by adding more choke.  When going at a steady speed, she is slightly juddery. All of this is emphasised when the choke is in, providing the engine doesn't stall. 

I have set the ignition timing, and ordered some new plugs, bosch w7dc as per the Haynes manual. 

I removed the carb, and have stripped most of it down. None of the jets were obviously blocked. 

Any ideas?  And approx, what jets should I be running, so can check to see if it is right. 
Should I get a rebuild kit for the carb for 20 quid to replace all the gaskets, seals and diaphragms although they look ok?  Or would it be wasting my money? 

Cheers
Rob

Is the Preheat pipe on the bottom still plumbed in? Is there any nasties building up in the fuel filter?

Chris

r_chez_08 said

Hi, 
My 1.3 with a weber 34ich carb is not running right! 
It is often hard to start when cold, and then needs choke to stay going. On acceleration, it would sound as if she is missing, which is helped by adding more choke.  When going at a steady speed, she is slightly juddery. All of this is emphasised when the choke is in, providing the engine doesn't stall. 

I have set the ignition timing, and ordered some new plugs, bosch w7dc as per the Haynes manual. 

I removed the carb, and have stripped most of it down. None of the jets were obviously blocked. 

Any ideas?  And approx, what jets should I be running, so can check to see if it is right. 
Should I get a rebuild kit for the carb for 20 quid to replace all the gaskets, seals and diaphragms although they look ok?  Or would it be wasting my money? 

Cheers
Rob

Different engine, same problem though- mine 'solved' by a clean of the carb, setup and flushing the pipes through following replacing the tank. Highly frustrating and think it was a combo of the issues- crud from the tank blocking the lines, getting in the carb and a vicious circle eventually leaving the car only running when the choke was out. Think this was the case as it was forcing more mixture into a clogged carb.
Apparently the jets etc were fine in the carb but after a bow out with the airline it seems (fingers crossed) to be working, the first time since I picked it up.

Thanks for the replies. I think the preheat pipe is on is that the one from the exhaust system to the intake manifold?  I will replace the fuel filter but it looks fine, I have replaced 3 petrol hoses in the Bay because they were perished and one was leaking. 

I boiled up the carb body and jets in citric acid solution, used to do this on my kart carbs, and it works a treat. Everything should be okay so ill reassemble the carb tomorrow. 

How can I check to see if the tank is full of crud? And surely the filter would stop it getting to the carb? 

Cheers
Rob 

Youd be surprised Rob, When my tank was full of crud my filter used to fill up after one day, and the carb float bowl would be full of black rubber dust from all the perished fuel lines as its so fine. Bearing in mind theres also a pre-filter on the front of the carb aswell. (Behind a brass plug where the fuel lines plumb on)
When i took mine apart i used loads of carb cleaner and the air line on low. Its great to see what you get out of it lol  The only way to check the tank without taking it off is through the inspection hatch under the back seat, and remove the tank sender assembly.

Thanks! I checked the filter on the carb and it was pretty clear, and there was practically no cr P in the bowl.

I reassembled the carb today, installed with a new gasket. Realised I set the timing with the vac advance on, so I took it off and re timed. Started up with no throttle and a little choke, turned the mixture screw out about 3 turns, runs pretty good! Idles around 700, sounds slightly lumpy, but not too bad. No smoke coming out of the exhaust which is a plus. There is still a slight miss when revved up, around 1000 rpm, but not as bad.

Ill take it for a run and see

Edit: if you floor it, there is a slight jump/ delay, and if you rev up really slowly, it struggles slightly going from about 1500 rpm to 1800 rpm.  Then again around 2500 rpm. It would stall out if you revved really slowly over 1500rpm, but I richened the mixture with the screw, and it doesn't stall now, still a little hesitation though. 

All of the above is remedied if the choke is pulled out about 2-3mm,  level with the dash, which makes me think that the mid range needs richening, as idle is fine, and same with top end, but with the mixture screw richened enough to stop the stalling, the idle is a little smoky- splattered black marks all over the drive! 

Is there a jet to richen mid range that I could drill out? 
Cheers

Edit2: pics  

Ok, put new plugs and fuel filter in. Played with the carb, and tuned it so it was a lean as I could get it without stalling out. Seems to run pretty good, Idles nice and low, with a bit of white smoke coming out of the exhaust. I'll take her for a run. Is the smoke normal? 

May just be a bit of moisture build up somewhere dude. Probably find it will clear after a good run.  

Hopefully. Black liquid also appears to build up on the end of the tail pipe, and splattered on the drive a bit. Unburnt hydrocarbons? 

yea thats literally moisture buildup in the exhaust system mixing with the soot spitting out. If i use mine for to many short journeys it starts to do that.

Ah really!  That's reassuring thanks. lll make sure she goes for a nice long run soon. 

OK, she went for a little run today, around 7 miles or so. Ran pretty good for the first 4 or 5 miles, then the problem came back again, exactly as before. I had a look in the fuel tank, doesnt look bad. There was a bit of black stuff at the bottom, nothing drastic, I'll grab a pic.
The fuel lines were quite perished at the ends, connecting to where the sender goes in, but chopped 1/2" of both ends and there not too bad. I'll probably replace them anyway for good measure.

This is really daffodil me off now. I am 17 in a week and a half and want to start driving. The plan was to drive her round the farm, so I got some practice in before I was 17, so much for that! Might just take her to a garage (please persuade me not to!!!!! Quitter!!!)
But when I will be driving her 45 miles a day, she needs to be right.

Oh and another thing- the oil light and buzzer came on whilst driving, the level is fine (actually slightly high) and the gauge was sitting at around 4-5 bar.
WTH is going on?!

Made an order with GSF. new gasket for intake and exhaust manifolds, new fuel lines coming off the sender, new rocker cover gasket and oil cap, as there was a small leak from there, the seal was missing. I may drain the tank, and put new petrol in, it may just be old fuel? Then I'll try blowing the fuel lines through. Cant think of anything else. Really confused cos she ran really quite well, so doesnt seem like a jetting issue!

If anyone has any ideas, that would be amazing cf_emoticons__BangHead:

I checked all the jets in the carb to make sure that they were correct, all fine except the e tube which is an f-6 instead of an f-7. Could this be causing an issue?
http://vwgolfmk1.org.uk/forum/index.php?page=topicview&id=small-block-carb-engines_2%2Fweber-34ich-tech-sheet

Flushed through the fuel system, siphoned the tank (wasnt bad, just thought there could have been water or the fuel gone off) replaced all bar one of the rubber fuel hoses, cussed and swore, replaced all carb mounting gaskets, removed the gouges from the adapter mounting plate (there were a load of straight scored lines), checked valve clearances and tweaked any that were out, new plugs and thats where I am at. Still misses when going constant rpm below 3000rpm. Could this be a burned valve?
Cheers
Rob

is it between 2600RPM and 3100RPM by any chance?

Gordonthegolfer said

is it between 2600RPM and 3100RPM by any chance?

Maybe, why? 

Mine used to do that. Spent ages trying to figure it out, gave up and took it to an auto tuner to have a look, they couldnt figure it out. One thing i forgot to try was HT leads, Put a new set of OEM HT Leads on, ,, Purred like a kitten    

Chris

Really?! Its had a new set along with other ignition components not long ago. It looks like it has these on it:
http://www.vwheritage.com/vw_spares_Ignition-Leads-Set-Mk1-056998031_act_shop.product_pID_55911105_lang_EN_country_GB.htm
They are bremi's and say '51 ohm' on the cap.

Just did a compression test. Forgot you had to do it warm. Got just over 50psi per cylinder, so I would presume its OK as they are all uniform? Therefore no valve issues thank god! I wouldnt trust the calibration too much tho, it was a cheap POS compression tester!!

Tried the spare bosch coil that was in the boot. Made no difference. I might order up some ht leads if you think it could be that, but they are pretty good,  as they are fairly new.

Bought some ht leads and new dizzy cap today. Installed, and she ran almost perfectly! 95%, thanks for that.

The only thing is that you still need to give it a little choke. Tried richening the mixture screw by 1/4 turn and it ran worse. Any ideas? Oh and she doesnt start as well as she should when warm.