[Ennio]

Hello, I´ve had some trouble with my 82 alfetta gtv tuning up specially with setting the carbs. I am a newbie alfa owner and as it is my first car I haven´t done too much DIY work.

I´ve just bought a timing light ("classic" not with rpm or advabnce measurements), a synchrometer and a colortune.

First I did the ignition timing, and set the timing at idle using the light with the P mark of the crank pulley. Then I sprayed carb cleaner by the carb´s mounts to see if I had any leaks but din´t find any, the car idled smoothly. To be sure, I disconnected the carb support rod and moved the carbs up and down to see if there was a change in the idle, as nothing happened I proceeded.
Secondly, I was going to set up the carbs since I had a smog test and they were crap! I disconnected the linkage, unscrew the balancing screw and the idle screw completely. Then I ajusted the balancing screw until it made contact with the lever, and did the same with the idle screw.
Thirdly, I adjusted the idle mixture screws completly and give them 5 turns out, reconnnected the linkage and started the car and started balancing the carbs.

I´ve had trouble to get a smooth idle, or make the car hold the idle, so it has been very difficult to balance them. Although I adjusted the idle screw the idle remaind the same, if I accelerated the car, when the rpms went down the car remaind at 2000rpm (I think that was the real idle which was set) and then solwly went down to my erratic idle. As it was geting dark I stopped.

I don´t know what to do, how to fix it, or if I have done something wrong. Please help!!

The car has twin Dellorto DHLA 40 carbs with Ram flo filters, cams and headers (donpt know the specs as they came with the car), bosch electronic distributor and Mallory Hy-fire 6AL ignition.

 

[catsboy]

Might try putting this in the 'Carburetors and Fuel Injection' forum...

 

[alfavirusnz]

Ennio, you need to set the carbs at an idle speed of 900-1000rpm. Allow the engine to get to normal operating temperature. Then put your Colourtune (great tool by the way) into the first plug hole, adjust that carb idle mixture (blue flame just leaned past orange)-you may then need to readjust the idle speed down. You can then do each cylinder the same way. After you have the mixture right you can then recheck carb balance. For some reason the 116 series do not idle (the engine bucks around a lot more) as smoothly as one of the earlier 105 cars with the same engine-perhaps its softer engine mounts.

Richard J
`65 Giulia Ti 1600, ``69 GT Junior, `74 GTV 2000, `76 Alfetta GTV, `77 Alfetta GTV, `84 GTV6

 

[Ennio]

Thanks for the advice Richard.

I re-checked the ignition timing. Then started using the colortune and the car`s idle went up, I re-adjusted it and continued using the colortune, re-checked carb balance and everything was ok.

Now I am confident with the carb`s set up, the car will mantain a very low idle speed, it is as smooth as a ported head!! never felt the car this way!!