ISO. Main and 2nd Jets 75 2f. (1 Viewer)

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I have a 75 FJ40 with 2F. Couldn't figure out why ran so bad and needed choke. Well, I am at sea level and it had high altitude jets in it (103/157)!!! I switched them [main to 2nd and 2nd to main] to test. Wow this thing actually has power!!!
So does anyone have a pair of jets around 140/220? That's what SOR states should be there. Its federal and I dont need to pass smog w a 75 in CA.
I could drill them but I dont have the bits.
Does anyone have some in this range?
No one seems to sell them.
I might try to find the bits still... but checking into MUD since it's an interesting situation and should be shared.
I'm in so California.
Thanks to all. Love MUD.
 
Here are some picts to add for this thread.

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i do not recall where i ended up, that was just one of several orders. im pretty sure i landed somewhere around 155-160 and maybe even larger than the 220.
i was changing jets taking it out and flogging it, then rinse and repeat. my carb showed up with like a 136/180 combo....no power and you could feel when the secondary butterfly opened.
the carbs are not the same for every year...there are differences in the venture opening sizes...among other things.
 
i do not recall where i ended up, that was just one of several orders. im pretty sure i landed somewhere around 155-160 and maybe even larger than the 220.
i was changing jets taking it out and flogging it, then rinse and repeat. my carb showed up with like a 136/180 combo....no power and you could feel when the secondary butterfly opened.
the carbs are not the same for every year...there are differences in the venture opening sizes...among other things.
That's interesting. All the charts show main jet max is 140. And that's only in 75. The other years were shipped with 136 amd even lower.
I ran the 159 that was in my secondary and put it in the main. Truck runs pretty good so far although now I will drill the secondary to 220.
You say you are most likely running about the same as me at this point (155-160 main). How is everyone else running such small main jet???.
 
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How is everyone else running such small main jet???.

believing the hype that the 2f is underpowered.....and having to pass to smog tailpipe tests
 
Start with 144 primary and 230 secondary for a '75 dated carb.
Thank you. It's interesting that most other threads talk about much smaller jets. I have a 159 in the main now and it seems to be strong. I will try leaner as a test later.
 
Thank you. It's interesting that most other threads talk about much smaller jets. I have a 159 in the main now and it seems to be strong. I will try leaner as a test later.
Clean the plugs or get new ones, drive and idle it then inspect plug color, that’ll quickly tell you if jet is too big/small. 159 may be good, but also dependent how strong your vacuum is. The closer to 21-22inHg (at sea level, adjust for your elevation), the leaner the jetting would need to be, oversized jets will mask vacuum leaks.
 
Clean the plugs or get new ones, drive and idle it then inspect plug color, that’ll quickly tell you if jet is too big/small. 159 may be good, but also dependent how strong your vacuum is. The closer to 21-22inHg (at sea level, adjust for your elevation), the leaner the jetting would need to be, oversized jets will mask vacuum leaks.
I am pulling 20-21psi at idle. Not sure of idle rpm but it is pretty low
 
Clean the plugs or get new ones, drive and idle it then inspect plug color, that’ll quickly tell you if jet is too big/small. 159 may be good, but also dependent how strong your vacuum is. The closer to 21-22inHg (at sea level, adjust for your elevation), the leaner the jetting would need to be, oversized jets will mask vacuum leaks.
Btw good advice to check plugs and go from there. And big jets can mask vacuum leak. Thank you
 

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