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Discussion Starter #1
I went through all the fuel and ignition systems today just to test and make sure they were all working properly as I have a misfire in cylinder 2.

The Ignition system was a bit corroded here and there, nothing too serious. I cleaned it all up, also discovered I had a bosch electronic ignition. A couple of wires were loose from the control module to I re-soldered the PCB. The timing was fine and all plugs had a spark.

I got to the fuel system and found that the air bypass screw for cylinder 1 was screwed fully home, although I am not sure of correct adjustment procedures. Is this normal?

I also found that the fuel mixture screw for cylinder 2 was missing. Obviously I need to fix this problem. Will a rebuild kit contain one?

Easy fix to what could be a complex problem! :lol:
 

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Not sure a repair kit would contain a mixture control screw - for later carbs these screws are tamper-proofed. I guess a call to a carb specialist would solve that problem, but I do recall buying a pair of 40IDF service kits and there were no mixture control screws, or jets of any description in them.

The air bypass screw should not be fully home. I adjusted all of my air bypass screws out 2.5 turns from fully home, which I think is the recommended starting point for tuning. If you have the individual vacuum guages set up on all 4 monitor points you can adjust the bypass airflow to smooth out the idle, but there is unlikely to be any major variation in airflow to each cylinder unless you have other problems. So a nominal setting on all 4 should be good enough.

When I took my engine out of the box I found someone had messed about with all of my bypass screws. The engine wouldn't idle worth a damn, and that was all that was wrong - one screw had one turn on it, another had 5... you get the picture.

Lauren
 

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Discussion Starter #3
Thank you, I will try 2.5 turns on all air bypass screws.

I had a look on delorto's official website to find a spares list. I need a washer, a gasket, a spring and the screw all at the grand total of about £7.50! :)

:thumbs:
 

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Imagine what you would have to spend to cure a similar problem with an EFI engine. Replacement ECU probably.

Carbs rule!!! :thumbs:

Lauren
 

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Discussion Starter #5
Imagine what you would have to spend to cure a similar problem with an EFI engine. Replacement ECU probably.

Carbs rule!!! :thumbs:

Lauren
They sure do!

Actualy I have a similar problem with my Barchetta so I will compare costs!

:cheese:

:(
 
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