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Discussion Starter #1
Hi,

I've got a problem with the Alfetta that when it gets hot in traffic and you accelerate normally it will lug as if you're in too high a gear or running out of petrol. If you put your foot down more (than you normally would) or change down it will be fine.

I thought it must have been carb related so had them rebuilt but am still not convinced, though it does run fine when cool. The fuel pump was tested at the same time and is good.

I've also installed a new fan switch in case but the fan workers fine.

Thoughts are fuel starvation but the pump seems to be ok, incorrect jetting or fuel vaporisation possibly. Also maybe it's getting just a bit too hot but I can't see a way to alter the temperature that the fan kicks in.

Thanks
 

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Timing? Harryf beat me to it....
From personal (painful! to the wallet) experience I'd check out the ignition system before spending time / money on the carbs.
Check the colour of the spark plugs after a blast (with a warm engine). The Haynes manual gives colour photos of the various permutations.

Subtle alterations to timing (by advancing/retarding the distributor) can have a major effect on driveability. If this doesn't work then a little 'fiddling' with the carbs to 'correct' spark plug colour is the next step
 

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Discussion Starter #4
Thanks both, ignition system has been completely replaced including a 123 distributor so that's all good.

I can easily have a play with the timing though to see if that helps.

Thanks
 

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I think the key here is "get hot in traffic". Fuel evaporation of some sort I would see as favorite.
 

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Mine does a bit of that- gets a bit twitchy/jerky when hot at low speeds - I put it down to the carbs running slightly weak because I have a Pipercross, they really need setting up properly but I cant really justify £300 + for a RR session - as you have a 123 fitted I would say its a carb issue
 

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Discussion Starter #7
As far as fuel evaporation goes is that a fault with the carb, if so which bit's to play with, I do have a bag of assorted jets etc. I could experiment with. The carbs are Dellortos and I remember reading somewhere that they do get hotter than Webers so need more cooling, I might try and run a pipe from the front directly to the carbs to maybe give a bit more air cooling??

I can try changing the mixture but it runs fine when cool.
 

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As far as fuel evaporation goes is that a fault with the carb, if so which bit's to play with, I do have a bag of assorted jets etc. I could experiment with. The carbs are Dellortos and I remember reading somewhere that they do get hotter than Webers so need more cooling, I might try and run a pipe from the front directly to the carbs to maybe give a bit more air cooling??

I can try changing the mixture but it runs fine when cool.
Not normally a problem with Dellortos - you could try shielding them from the engine with some fire proof insulation temporarily just to see what happens but its a tight old space under bonnet - ethanol mixed fuel can cause problems - what do you use? - best to use highest octane you can - Tesco Momentum and Shell V are the highest - I've got a cold air feed on mine - had to change the bottle for a much smaller one and run some flexi duct ( old mini trunking) in from behind the bumper, but of course that doesn't work very well at low speeds or stationary - non injected Alfa's do love cold air tho.
 

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Discussion Starter #9
Yes that's the first thing I'll try, certainly the cheapest option, I don't really want to start messing with the carbs as the rebuild and tune was expensive.
 

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Discussion Starter #10 (Edited)
I've got all the bits together, an asbestos (substitute) sheet from science to put under the carbs and 6 Pringle tins from the kids at lunch to make some temporary air feeds from the front, school is a great source of parts!

Maybe a GTV6 type air scoop might help too!
 

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I think something tasteful like this would set it off nicely ...........
 

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Discussion Starter #12
Now we're talking, I can make one of those from the spare Pringle tubes!
 

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Discussion Starter #14
I've rigged up a pretty good air tube, no where to put the heat shield without fouling the linkage.

The carbs are actually Solex (don't know I forgot that, too many cars too many different carbs) if that makes difference.

The air filter was past its best too which wouldn't have helped so I'll order a new one of those tomorrow.
 

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I've rigged up a pretty good air tube, no where to put the heat shield without fouling the linkage.

The carbs are actually Solex (don't know I forgot that, too many cars too many different carbs) if that makes difference.

The air filter was past its best too which wouldn't have helped so I'll order a new one of those tomorrow.
You could try some of that flexible heat shield they sell on amazon
 

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Do any of you here ever louvre the bonnet to help with the under bonnet temps?
Have to say I hope not, just my personal opinion but I think it would look awful, I've never had overheating probs even in the heat of summer, don't know about the S4 but the S2 is well provided for in the cooling dept. I binned the fan and fitted an electric one and never looked back
 

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I would be surprised and darned angry if I had paid good money for carbs to be setup and the tuner did it with a filter less than perfect!!

Also a blocked filter should make it run rich so engine getting hot is less likely to cause poor running.

Your starting point should be plug colour check, ignition timing check including checking that it is advancing and retarding smoothly, check that the fuel pump is delivering adequate flow at idle, check fuel accelerator pump for correct delivery and that is just the starting list. Diagnosing and fixing this type of problem can be a pain.

Note that moving the timing is likely to affect the idle speed so you will need to adjust for that on the carbs.
 

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Discussion Starter #19
Thanks kandlbarrett, I'll run through those tomorrow. No he didn't mention the filter but it certainly needs changing!
 

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Question: which side is your HT coil?
I had hot starting issues on my S3 (solex too). Replaced and moved the HT coil to the carb side - solved.
 
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