long story short but i finally ordered the jets that mazda recommends in the comp book for a PP 12A.

with the 80 idle jet and 120 holder like mazda says it idles nicely at 1000rpms, but the idle screws are all the way in.

i have a 70 idle jet, would this be too big of a jump for the adjusting screws?

or should i get a 75 idle jet.

basically how big of a jump is 10? 5? how big of a range do the mixture screws have.

i'd go do it, but its too loud, and i need a fan on the radiator...

 

10 is BIG.

If it's idling at 1000rpms, the idle speed screw isn't screwed in all that much which is good. So try the 75. A richer idle fuel jet really helps the progression circuit. And, with those big intake ports opening quickly, it'll need it.

Couldn't hurt to try the 70 you have now. Got a wideband to monitor mixture changes?

 

Sounds to me like the idle screw is in all the way. Yes try the 70s since you have them. Maybe the idle screws can be backed out a turn or two, which would put them more in their normal range.

 

Where did you buy your jets from?

 

well i put the 70's in, and initially it made no difference. but i think its because the idle speed screw was in too far.

today i warmed it up, and turning the idle speed screw out, lowered the idle, and then it came up, with the mixture screws about 1/2 turn out, which seems good! idle is a machine gun like 800

my next step is to put the wideband in...

 

ebay, i think it was user alfa1750. jets were inexpensive, but 2 weeks to get, which makes EFI much better right there! no waiting, you push button!

 

if its all the way in, then it is the jet is too big. size of ur venturies and exhaust? thanks to index/number drills, I can re-use the VW jets that I've collected over the years.

 

carb is setup exactly like the comp manual

43mm venturi
f8 em tubes
230 main jet
130 air
70f10 idle jet
120 idle holder

exhaust is header into 3" glasspack into a borla