Possible running issue!!

[leggattr]

Right coming home from work tonight running the new engine set up of 13sb and weber 32/34dmtl I got to a straight road so decided to put my foot down alittle.
Anyway got into 4th gear with my foot on the throttle and it started to slow down, this happened in every gear getting slower when pressing the throttle until I stopped and cut out.
Once stopped I got it going ok and took it easy the rest of the way home.
It felt like the brakes where going on every time I pressed the throttle.
Could this be over fuelling?
I'm still not sure if all the vacuum pipes are linked correctly at the mo so could that be an issue? At the mo the inlet is connected to the back of the carb and the dizzy vac is connected to the front of the carb (lower connection). The weber guide says to blank the inlet and front of the carb and connect the dizzy vac to the back of the carb so should I give that a go?

Sorry for huge essay but spent a lot on this so what it running right.
Richard

[kent14sr]

Yes make sure the vacuum connections are correct.

Sounds like a fuelling issue on the second chamber perhaps. Is the carb jetted for your engine?

[leggattr]

When using conza123's set up as an example my vacuums are different and he used the weber guide so il swap them this morning.
The jets are correct for the car. Does that mean not to put my foot down or do I need to control the pressure of the fuel going in?

[leggattr]

Drive into work was ok today and I didn't leave the manual choke on for that long. Last night I did so could that with me trying to go full throttle be the issue maybe?

[kent14sr]

So today it was all ok?

You have to be careful with the choke as it will flood the engine if you use it for too long.

The symptoms you decribe almost sound like its not getting enough fuel, but could easily be the opposite which would apply perhaps if choke was out too long. It sounds like it could be an issue with the second venturi (choke), which only comes in on full/heavy throttle.

If it is vacuum related it will usually either not idle right or at all.

EDIT - the fuel pressure should be fine at standard pressure. I assume you are using an OEM mechanical fuel pump?

[leggattr]

So this morning same issue again, after coming off a large roundabout with alittle pace the carb started to not accerate but slow the car down. When I pulled over it didn't cut out but struggled to rev cleanly until I left it for a moment. On way home was fine.
What I did notice the other day when fiddling with the second Venturi on idle it shut the engine off so could that opening have some cause to my problem, maybe not closing?
I'm going to look at adjusting the idle enrichment screw to see if its a lack of fuel going in.
I say this also because when pulling away in 1st the car can hesitate on a low rev so needs a heavier foot!! Could that be a sign of not enough fuel going in too?
Just don't have the funds to give to a garage yet so want some reliability for now.

[therealnovaboy]

what was the temp outside ? could be freezing up as the fuel atomises as it comes out the jet. used to get this all the time in the winter months. when you stop the heat soaks up from the head and melts it again.

[General Baxter]

im voting carb ice, sounds like what happened to me on my 1.4 with 32/34

[leggattr]

It's warm still in kent! Well no where near cold enough for ice yet anyway. Iv adjusted the enrichment and so far no hesitation but the engine is still warm. Will try to test again later.
What are the symptoms of fuel starvation on a carb?

[therealnovaboy]

In that case Clean the carb and make sure its spotless before tuning out dirt in a jet.

[leggattr]

Been rebuilt with new weber kit and everything cleaned including all jets etc.

[therealnovaboy]

Its funny its working one muinute and not the next. Has it had new HT leads put on it recently?

[leggattr]

Brand new everything pretty much. New leads and plugs. Just been out for another run, starts ok pulls away fine at low speed and high speed, a few roundabouts with alittle gas and straight line speed which was all fine.
Not counting my chickens yet. Got football early tomorrow which isn't a long drive so see what it's like in the colder weather with a cold engine.

[kent14sr]

Carb icing sounds favourite as Baxter said!

Try putting a warm air pipe from the exhaust manifold to air filter and see what that does!

If your running with a K&N filter that could be the issue - alternatively put on the standard air box, I have the adapter somewhere for one I think!

Just another think - check the brake servo vacuum pipe at idle. Move it around whilst its idling and see if anything changes.

What RPM does it warm idle at?

[leggattr]

Iv got it idling between 1000-1500rpm. I'm using a ramair foam filter rather than K&N. I don't have the original sr filter as the pierburg had a K&N on that. Manifold is a 4 branch.
Iv not connected the oil breather to the filter, it has a seperater breather filter on the end of the pipe. Poss warm are coming from that but as it blows alittle smoke I didn't want to connect it back to the carb.

Edit:
Still don't think it's cold enough for carb freezing at the mo.

[therealnovaboy]

It doesnt need to be that cold. Its to do with the Joule Thompson effect. When the fuel is forced through a small hole it atomises and expands creating a cooling effect. its the same as when you spray deoderant on it feels cold as it changes from a liquid in the can, to a gaseos vapour in the air.

definitely get the standard air box on it in the winter.

[General Baxter]

what you got to remember is,

5 or 6 degrees air temp is low enough to cause carb to freeze,

fans blow cold, when its hot, this is whats going on in your carb on a massive scale, as its sucking cold air, it makes it even colder, enough for the fuel vapor to freeze

[leggattr]

Ok I see always assumed it was when its very cold that carb icing accured. Would linking my breather to the air filter help? I didn't originally do because i wanted to reduce emissions for mot purposes but if warm air comes from that then that may help issues.