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Old 04-14-2018, 11:17 AM
KirkV KirkV is offline
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Join Date: Jul 2011
Location: Peoria Illinois, il
Cobra Make, Engine: Superformance #678
Posts: 264
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Default Idle Mix cylinders Different



So I have my Inglese IDA system and installed it last fall. I have an issue I don't know how to resolve or if it is really an issue at all?
I set the velocity with the velomiter and got all cylinders balanced ok, but when I go to set the mix screws I started at 1 turn out on all of them.

The front 2 sets of carbs would stumble when starting to screw them in like I would expect. I opened them to about 7/8 open and they come back nicely.

Here is where it got weird, the rear sets of carbs when I screwed them in never went away like I expected. So I opened them more and the engine picked up rpm and idled smoother at about 1.5 to 1.75 turns open. I have tried different jet sizes and get the same results

I checked the air volumes again and they were all even. At this point I thought I had a intake leak so checked the whole thing over with raw propane and found nothing.

I have now pulled the intake and everything looked good on the gaskets and no issues found. I am trying to get rid of my stumble at 2000 to 2500 rpm by adjusting idle jets and air correctors but have a deuce of a time with it.

I am headed out to get new intake gaskets and start all over again, but does anyone have an idea of why the rear 4 pistons want more mix jet?

I have taken the webers off and examined the small holes that feed fuel in above the mix jet needle valve and found all of them to be open. The hole the needle valve screws into is open on all 8 as well.

I will get it reassembled tomorrow and try to set it up again, but I am at a loss??????

Thanks Kirk
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