A/F mixture / Timing Relationship?
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
All we can do is explain to you the BEST way to adjust your carb. It is YOUR choice as to which method you use. If your method actually worked well, I don't think you would be asking for assistance on this Forum. Either way, I wish you luck in getting your engine running well.
Race Director
Joined: May 2006
Posts: 18,737
Likes: 2,583
I know I'll catch hell for saying this, I have been adjusting idle speed using a tachometer since around 1968, never used a vacuum gauge.
Set your idle speed screw to whatever speed you want.
Then turn either idle mixture screw in a 1/4 turn, if the idle drops turn back out a 1/4 turn.
Then turn the other idle screw in a 1/4 turn, if the idle drops turn back out a 1/4 turn.
Continue doing this until both screws have produced that drop in idle and you have turned them back out 1/4 turn once you hit the idle drop.
Readjust your idle speed if necessary.
Reconfirm both screws cause a drop when turned in a 1/4 turn.
Last edited by MelWff; Jul 16, 2020 at 11:57 AM.
Thread Starter
Drifting
Joined: Nov 2013
Posts: 1,806
Likes: 258
From: Dublin Ohio
Thanks guys. Like I mentioned, I noticed that as the idle became more rich both RPMs and vacuum increased because I had both tach and vacuum gauge hooked up at the same time so they work in accordance.
I just have to cut it off at the point it floods.
I went through the 3 and 4 turn area today with RPM at 850 which is where Lars said he sets it and I settled on a setting.
I just have to cut it off at the point it floods.
I went through the 3 and 4 turn area today with RPM at 850 which is where Lars said he sets it and I settled on a setting.
Thread Starter
Drifting
Joined: Nov 2013
Posts: 1,806
Likes: 258
From: Dublin Ohio
I just mentioned 3-4 as the range I focused on because it flooded at 4 and it sputtered at WOT at 2.5.
I went through every 1/8 th of a turn between 3 and 4 and settled on 3.5 then tried what you could call 1/16 of a turn above and below 3.5 and ended up at what amounts to 3 and 9/16 turns.
I went through every 1/8 th of a turn between 3 and 4 and settled on 3.5 then tried what you could call 1/16 of a turn above and below 3.5 and ended up at what amounts to 3 and 9/16 turns.
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Thread Starter
Drifting
Joined: Nov 2013
Posts: 1,806
Likes: 258
From: Dublin Ohio
That checked out fine. I thought I could always hear the squirts when I pushed the pedal to set it up to start - just never did it by hand.
And it really likes the set up where I have it.
No issues any where and it almost seems fast.
And it really likes the set up where I have it.
No issues any where and it almost seems fast.