Alfa Romeo Owners Club of Australia Forum

Technical => 116 Series (Alfetta Sedan/GT/GTV & Giulietta Sedan) => Topic started by: Alfapride on April 05, 2021, 10:40:20 AM

Title: Alfetta gtv carb set up
Post by: Alfapride on April 05, 2021, 10:40:20 AM
Hi fellow Gtv owners wondering whatís the best carb set up you have found with a stock engine and 105 cams? I just looked at my carbs which I bought refurbed years ago to see their spec look like the below
Cylinder 1 Emulsion tube 7772.10 with 148 jet
Cylinder 2 7772.8 with 148 jet
Both with 62 idle jet

Cylinder 3 7772.11/148
Cylinder 4 7772.8/148
Both with 62 idle jet

210 mains

Not sure which choke not sure how to check them yet will look but surprised the tubes werenít matched?

The carbs are dellorto dlha 40-h

Thanks in advance for any set up suggestions
Title: Re: Alfetta gtv carb set up
Post by: carlo rossi on April 05, 2021, 12:47:51 PM
First step
When you say you have 105 cams what are the next 2 numbers after that
Before you jet this is very important to know
You also want the emulsion jet to 7772.8 all 4 of them
Then we will move on
Happy Easter
Title: Re: Alfetta gtv carb set up
Post by: Alfapride on April 05, 2021, 01:15:16 PM
Hi Carlo happy Easter to you also! I donít know the number now but I know itís the 105 pre emission cams both for the inlet and exhaust it was an upgrade done long ago and recently verified when I got the steam seals replaced and tappets adjusted - where do you recommend I buy the matched emulsion tubes?
Title: Re: Alfetta gtv carb set up
Post by: carlo rossi on April 05, 2021, 01:24:56 PM
I go to dellorto uk Iíll assume they are 10548 cans
Youíll need the emulsions air correctors 210
Mains 152
Idle 58
Accelerator pump jet 38 x4
Title: Re: Alfetta gtv carb set up
Post by: Alfapride on April 05, 2021, 01:29:14 PM
Hi Carlo I have a spare cam pretty same one in the car says 10548 03 200 if that helps Iíll get the bits for the car and revert thanks for the advice...how do I check the choke or access them? I recall being told 33mm was way to go but not sure whatís in mine?
Title: Re: Alfetta gtv carb set up
Post by: Alfapride on April 05, 2021, 01:30:19 PM
Also how would I check the accelerator pump?
Title: Re: Alfetta gtv carb set up
Post by: Alfapride on April 05, 2021, 02:46:17 PM
Found the accelerator pump jet ...42mm so disappointed  bought these from an Alfa specialist who rebuilt them and all the specs look wrong - any instructions how to check the Venturi ? Looks like Iíll have to do one order and get it right!
Title: Re: Alfetta gtv carb set up
Post by: carlo rossi on April 06, 2021, 10:35:09 AM
the chokes come out after you loosen the side grub screws
they should be 32mm but with those jets they maybe bigger
i find 34mm the best all round not worth 32 to 33 difference is not worth investment
Title: Re: Alfetta gtv carb set up
Post by: Alfapride on April 06, 2021, 10:48:43 AM
Thanks Carlo confirmed they are 32 chokes will stick with them based on your advice, will look to get the other bits and report back once all installed thanks for your help
Title: Re: Alfetta gtv carb set up
Post by: Alfapride on April 17, 2021, 01:28:12 PM
I go to dellorto uk Iíll assume they are 10548 cans
Youíll need the emulsions air correctors 210
Mains 152
Idle 58
Accelerator pump jet 38 x4

Thanks Carlo I have put in the 58 idle jets and 38 pumps and matched all the emulsion tubes to .8 waiting on a manometer to tune properly but seems to be good so far - matching the emulsion tubes appears to have made a big improvement to hot starts - easy to start now before always struggled
Title: Re: Alfetta gtv carb set up
Post by: Colin Edwards on April 19, 2021, 08:12:49 AM
Dropping down to 58 idle jets from the 62 resulting in leaner idle and progression will have helped hot starting.  Emulsion tubes should only enter the equation when the mains come on line. 
Title: Re: Alfetta gtv carb set up
Post by: carlo rossi on May 03, 2021, 01:51:06 PM
now thats all sorted warm the engine up  then screw in all all 4 idle mixture screws all the way in and turn them out around 3.5 turns ( should be lean)
and then increase the idle to around 1200rpm using the idle screw
turn all 4idles  anticlockwise half a turn
did the engine revs rise or drop
if it raised do this again if it drop turn clock wise 1 turn ( halfa turn from start point )
keep doing this until max revs are acheived then turn 1/4 turn anticlockwise to finish
this is to keep temps down

Title: Re: Alfetta gtv carb set up
Post by: Alfapride on May 03, 2021, 10:45:46 PM
Thanks Carlo rpm raise the more you richen the mixture I played around with them and one carb circa 8 turns and the other is 7 i reset the idle to 900 post the mixture adjustment seems to run pretty good now wonder if itís worth experimenting with 60 idle jets and 40 accelerator pumps or leave as is - I also have the 152 mains but still have the 148 I hadnít changed them over yet
Title: Re: Alfetta gtv carb set up
Post by: Craig_m67 on May 04, 2021, 08:30:34 AM
Quick trip to Bunnings/Aldi and you can make your own manometer
(Worked perfectly)

Title: Re: Alfetta gtv carb set up
Post by: Alfapride on May 05, 2021, 04:24:24 AM
Cheers Craig I do have a manometer certainly helps with the balancing and tuning but great suggestion love the DIY!
Title: Re: Alfetta gtv carb set up
Post by: carlo rossi on May 05, 2021, 09:34:51 AM
8 turns seems excessive are you sure its not 8 half turns the
stock setting is 4.5
how ever yes if its 8 turns then the 60s are the better option
and put the 152 s in
Title: Re: Alfetta gtv carb set up
Post by: Alfapride on May 09, 2021, 07:25:38 PM
Thanks Carlo itís running well as is with the below spec so will keep it as is for now but if I get the itch to tinker I have all the parts to do another set up
148 mains
32 chokes
58 idle jets
38 accelerator pumps
.8 emulsion tubes