Very fast idle

[simonpen]

After a bit of a layoff and trouble finding a spark my Rallye 1.3S burst into life and went straight to almost 3000rpm. Turned it off, each time I start her the same thing happens. I have disconnected the accelerator linkage, wound out the idle speed screw, no change. The butterflies are closing. Air leaks? I have replaced the gaskets either side of the carburettor mount(s), the rubber mounts look alright, no obvious cracks., ageing. I disconnected the servo hose, revs go even higher, put my finger over the manifold take-off revs go back down to 3000. Timing is correct. I had rebuilt the carbs some months ago and afterwards everything appeared ok, she ran quite well. Interestingly she now needs no choke to start, quite cold today, started second time, straight to 3000 and quite smooth. Any ideas? Should I go back to Jaguars?

[Richard Fridd]

Is the choke stuck on?

[simonpen]

Not that I can see externally,  I have disconnected those as well and manually yanked them to what should be the shut position.
 

[lancialulu]

Sounds like an air leak.... spray wd40 around to see if revs drop momentarily.

[nistri]

And if you cannot detect any air leak, check the needle valves, they can become erratic in their up and down operation particulalry when the engine is not used for some time, Andrea. PS:  no need to go to Jags, you probably already have their braking system if you car is S1.

[simonpen]

I started her up and sprayed WD40 around, nowhere seemed to make any difference. I was about to take the tops off of the carbs to check the needle valves when I thought I might try some brute force. The air filter box is removed so I took hold of the rear carb and pulled it upwards and lo! the revs dropped. Tried the same with the front carb and the revs went up, if I pull the rear up and push the front carb down the revs die away dramatically, indeed the engine cuts out. I suppose this means that the rubber mounts need replacing although they look ok. Is there any advantage to the one-piece mount as opposed to the separate variety? 

[nistri]

No real advantage in either type: essential to have a support bar under the air filter otherwise the carbs move and the spacer can crack, Andrea

[Tindrum]

The affect of moving the two carbs independently is merely making an adjustment that the balance screw makes.
If there are "canaries singing", in the immortal words of Harry Manning, that's a clear indication of split rubber mount(s).
If not, it probably just means a bit of expert adjustment is in order.
Speak to non-member Paul Leclercq (var1016@gmail.com)
He's very good at carbs, and Fulvias, generally.
Good luck.
Justin

[chriswgawne]

I am always surprised how many Fulvias have had the carb support removed. It really is necessary.
Chris

[simonpen]

Tindrum has it. I couldn't understand how yanking one carb up and another down worked and decided that I must just have been moving the spindles and affecting the balance of the carbs and so revisited the balance screw; I say revisit, that may not be accurate. All much better now and I shall flog myself with some heater hose as a penance. Paul Leclercq? Is that he with a cigarette holder that worked with Barry W some years ago? It was meeting that crew that convinced me I had done the right thing becoming a Lancia owner.

[Tindrum]

Very pleased we found the problem.
As mentioned by CG, if the carbs are being run with the airbox, that's a very heavy assembly for the rubbers to support unaided. The brace below the drip tray must be adapted/utilised.
Personally, I think carbs alone aren't such a problem but, for the sake of longevity, a good idea.
(My throttle bodies are very light, so not a problem).
Paul Leclercq is indeed ex- Evolution Engineering/BWE/Italtune, as am I, to a degree, and we both learned a lot from Barry W., and Harry M. before then.

[my69S1]

Does anyone have a picture of the support for the air box?  I am missing mine and the parts book isn't very clear.  I would like to know what it looks like.  Thanks.

[chriswgawne]

I have one spare 35mm diameter flexible carb mount in the UK in good condition if anyone needs one. No reasonable offer refused.
Chris

[davidwheeler]

Does anyone have a picture of the support for the air box?  I am missing mine and the parts book isn't very clear.  I would like to know what it looks like.  Thanks.

It is just a bit of steel tube with the ends flattened to allow holes for the fixing bolts to go through.

[Richard Fridd]

Does anyone have a picture of the support for the air box?  I am missing mine and the parts book isn't very clear.  I would like to know what it looks like.  Thanks.