Club 80-90 Forums

Hi all.

Air-cooled t25 2.0 ltr in need of some love. Noob here too so please answer simply haha

Firstly she starts okay most of the time but sometimes she doesn't fire up and I have to give her a couple of minutes. Starter motor is definetley turning over but just no fire up.

Secondly she sometimes struggles to hold idle more than a minute or so. Just seems to drop off and die. Doesn't happen all of the time but its a concern when at traffic lights or parking etc.

Thirdly when she does die on a hot engine she really struggles to restart and I have to give her 5-10 minutes before she will restart.

I've added a picture of the engine bay incase that helps.

Thanks for any advice xx

Hello,

...and welcome to the world of Air-Cooled Bliss..

OK, so as you have probably realised, your biggest problem is the Weber carbs setup....

You have no chokes or air-pre heat system, so it will run poorly until warm.
At best you will end up with a compromise where the carbs and timing are set up for running hot, with a reasonable tickover and emissions, with consequent difficulties on cold starting.

I would like to see a proper vacuum pipe (nylon) from the distributor to the carb.

There is a spark plug 'hat' missing on nr 2 cylinder.

Having the crankcase breather feeding into the RHS carb air filter is not a pretty sight..

That is a crazy oil pressure sender/switch.

You have a points and condensor SVDA distributor.. if you do not know these, then fitting a Powerspark may improve things...
https://www.youtube.com/watch?v=KkyBAMMHpa4

Hope this helps..

Cordialement,


 

Hi

This is fantastic except I have no clue about what you are talking about

When you say 'proper vacuum pipe' which one are you talking about exactly and what is wrong with the one i have at the moment?

I understand the spark plug hat. Can I just buy those off the shelf?

what is the crankcase breather? And where should it be going instead of the rhs carb?

Oil pressure switch sender? Explain?

Many thanks
I'm a total novice but I want to learn everything. 
People like yourself save the day everyday!!

Hello,

OK, so the vacuum pipe (carb to dizzy)should be made of nylon, with a short rubber tube at either end.
Because: when the engine accelerates the carb  vacuum tube sucks some of the air out of the canister on the distributor, giving the timing advance needed, if the tube is all rubber, like yours, then you lose some of the vacuum effect.

The crankcase breather tube is in the middle of the engine, under the enormous rubber pipe connecting to the RHS carb air filter. So, as the engine is worn, there is oil contaminated air under pressure being fed into the carb. this will unbalence the carbs.
This is probably why your right hand filter looks shonky...

I take it you have a retrofit oil pressure gauge on the dashboard, hence the exotic sender/sensor.

Cordialement,

Ah okay I will change the pipes to nylon then. Thanks for that. That will certainly help.

So where should the crankcase breather tube be heading to rather than the rhs carb?

Yes the dash board is an exotic mix of retrofit gauges and flashing lights. Thats a job for another day!!
When you talk about the exotic sendor sensor which part do you mean?

Many thanks

Hello,

The crankcase breather should go into the VW airbox...which you do not have....

The exotic sender/sensor is attached to the long braided pipe coming out of where the oil pressure switch would be...

This will show you whats what:   https://youtu.be/rQp-CP6JJwc

Cordialement,

Its funny you say that because I have looked at many other engines of this age and seen that they have the breather boxes and wondered why mine doesn't. I sort of assumed that it worked a little differently but maybe not.

A separate point, but worth sorting is the opening just to the left of the air pipe, front/center/right of the engine. This would usually feed warm air to the air box on a cold day to prevent icing. Un capped, it will feed hot air into the engine cooling air.

​​​

Hey.
Thanks for your replies.
The van is in the garage and being looked at tomorrow (monday)
I've also ordered a second hand full breather box/air filter box to fit to the carbs instead of the current air filters and to fit to the air intake pipe.
I feel that that is what it should have and what it potentially needs. I think the current air filters fitted in the picture above are just struggling too much to get enough air.
We shall see what happens

Also when restarting always have foot on accelerator when cranking. Pretty sure it’s proper starting procedure on CU engines in the manual


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Hello,

Jakew1610 wrote: ↑04 Jul 2021, 20:33 Hey.
Thanks for your replies.
The van is in the garage and being looked at tomorrow (monday)
I've also ordered a second hand full breather box/air filter box to fit to the carbs instead of the current air filters and to fit to the air intake pipe.
I feel that that is what it should have and what it potentially needs. I think the current air filters fitted in the picture above are just struggling too much to get enough air.
We shall see what happens

I think you will struggle to fit the original air box, as the carburettors cross bar is much further forward with webers...

We shall see what happens...

Air-Cooled Bliss..

Cordialement,

hi.

yes talking to the mechanic today he also thinks it will be a tight fit or possibly impossible and possibly it is a wasted purchase. 

Possibly needs an electric fuel pump as ive found fuel evaporation an issue myself on twin carbs, you switch off and it boils the float bowl dry hence why an electric will help prime everything

Use a fuel pressure regulator, new hose and clamps and you'll be fine