Takes 20mins to warm up!

[ddffrost]

Hi,

Been out in my van and loved every minute of it but its taking about 20 mins of trying to drive from one junction to the next without the engine cutting out and even when its warm it still cuts out at junctions occasionally?

Any idea's? I think it might be something to do with the carb but i'm not mechanically minded in the slightest!

Thinking of replacing the carb for something with a bit more power?

Any thoughts?

Cheers


Dave

 

[Fraggle]

Sounds like it could be Inlet Manifold Icing......ooh sounds bad doesn't it!!

It not but it is a bugger to drive like it!!!

Basically, this usually happens when the carb is sucking through really cold air (hence this time of year). The air and fuel try to mix but they have to pass through the manifold which if standard is pretty long. The pipe just below the carb will be freezing cold and possibly have frost forming on the outside if inlet manifold icing is happening. This happens because it is miles from any warmth and can take up to half an hour to warm up thus making a nice lovely warm pipe for the fuel mixture to pass through.

You can buy something called an IMDU which is like a little leather jacket that you connect around this pipe and wire up to the coil usually. These are like hot water bottles for the poor little manifold pipe.

I've not used one so can't say what they are like??

I used to block off the fresh air intake on the air filter in the winter so the air is piped up from the exhaust. This helped a big deal.

Make sure your carb is set up right with the mixture settings and timing is pucka but other than that it's kinda how it is really.

Before investing in twin carbs (which warm up really fast so no icing probs) I became bloody good at balancing my foot on the accelerator pedal whilst braking and operating the clutch to stop it stalling in the mornings!! :lol:

Good luck and hope this helps 8)

 

[pete nice]

Start at the begining. Set the valves when it's cold, check the points gap & pull the idle jets out of the carb & make sure they are clean.

Check that the choke mech is moving freely & coming on when it's cold.

The other thing to check is that the pre-heat pipes to the manifolds are getting warm. A cold manifold with play havoc with a cold engine, even causing frost to form on it.

 

[Fraggle]

yeah also what Pete said for sure.

The cold weather can exploit any weaknesses in an aging v-dub :wink:

 

[Harlequin]

Stock air filter or shiny after market ?
The small after market one stuck on top of the carb
on a cold/damp day sucks cold +damp air=icing as explained
by Fraggle

 

[ddffrost]

i'm slightly confused by all the technical stuff but cheers

its a stock carb by the way

thinking about twin carbs to get some more hp but some friends have them and they seem to be more trouble than their worth?

 

[Fraggle]

Ask Santa for the John Muir book for Xmas......helped me understand loads!!

 

[clyde]

As mentioned before sounds like carb icing. Used to happen to mine. I used to cut out at the first 5 or so junctions, swith it off and restart.
I tend to give it 5 mins or so warm up on the drive, then turn it off for 5 mins or so then restart. That seems to cure mine.

 

[ddffrost]

hi,

yer i tried warming it up for 5 mins before i left but it wont even run without constantly reving the nuts of it.

think i might invest in a service kit then a rolling road tune up!

Dave

 

[Loxy]

Never had icing myself, but apparently one way to help prevent it is to run the engine for 5 mins or so til it nice and warm, then turn off the engine for a few minutes - apparently the heat from the engine then has a chance to heat the manifold etc and helps prevent icing.

The above of course is no cure for fixing the problems as mentioned by the others, a non-stock exhaust &/or air filter will also not help with pre-heating the manifold.
Have you got a thermostat fitted & operational?

 

[pete nice]

I think there is more to this than carb icing. If it plays up for 20 mins, then I think you need to look further. do a basing engine set up first before you mess with anything else.

My advice is always to drive straight away, not to try & warm the engine. THe quickest way to warm it up is to drive it.

That said, the above is true that after a brief period, if the engine is turned off the heat with rise to the carb & defrost it.

It is the cold fuel mix that freezes the manifold.

 

[Tofufi]

When was it last serviced?

Mine felt a bit down on power, cut out at junctions for the first 20 mins etc. Turned out to be the points gap being wrong

 

[ddffrost]

Hi,

it was service just before i bought it about 3 months ao but not been used a great deal as i've only just got it registered!

might invest in a service when the season starts again!

Cheers

Dave

 

[speedwell68]

i'm slightly confused by all the technical stuff but cheers

its a stock carb by the way

thinking about twin carbs to get some more hp but some friends have them and they seem to be more trouble than their worth?

Depends on the dual carbs in question. Genuine Dell'orto or Weber 34s if set up correctly should be as smooth as can be, give you a mild hike in power and return a much better MPG. My '68 has Dual Dell'orto 34 FRDs and will do 60mph up hill and down dale and give me 31mpg if I am careful.

 

[Tofufi]

You should try servicing it yourself - it's a great way to get to know the mechanicals of your van and will save you money when these beasts need servicing every 3000 miles

 

[ddffrost]

hi,

yer thats the plan!

got a mate who's going to teach me!

might be worth a rolling road tune up at some point though!

cheers

Dave

 

[pete nice]

A Vw is so crude that a rolling road would be a waste of money. They are only really of use if you are trying to jet carbs. There is no reason to think your jetting is wrong. I do these sort of setups all the time on cars with similar problems. You can normally get it a hell of a lot better. Sometimes a new manifold or a par of carbs is the answer, but you need to get it to that point first.

It's a shame you are so far away as you could get an answer to what the problem is in under an hour.

 

[ddffrost]

hi,

yer i know the mechanics arent to complecated but i'm a total novice mainly due toe fact i spend about 50 hours a week sat behind a desk or drawing board!

sure there are some vw garages around here but need to learn for myself i guess!

maybe santa will bring me some twin carbs for christmas!

 

[ddffrost]

i'm slightly confused by all the technical stuff but cheers

its a stock carb by the way

thinking about twin carbs to get some more hp but some friends have them and they seem to be more trouble than their worth?

Depends on the dual carbs in question. Genuine Dell'orto or Weber 34s if set up correctly should be as smooth as can be, give you a mild hike in power and return a much better MPG. My '68 has Dual Dell'orto 34 FRDs and will do 60mph up hill and down dale and give me 31mpg if I am careful.

how much would i be looking at for genuine Dell'orto's then mate?

And where would you find these?

 

[Guest]

best thing to do even if your thinking about twin carbs is to buy a service kit @£4 for the existing carb and take it off give it a good clean, replace all the gaskets, float needle valve, O rings etc, see if it works any better.

i was able to refurb my carb with ease, running like a dream now, and ive never worked on any engine before. so if you replace it you still have a working one to sell.