Anyone who has used Bill Murrin carb synch tool

[XSive Okie]

So you can only adjust each carb to the other ones, but not a pair? Don't know if that's a good idea or not, when I take the time to do mine, I want them to be correct. I guess for a baseline to get you up and running it would be okay.

[BA80]

About 90 miles straight west on Hwy 412, like your leaving out of Sapulpa or Sand Springs. Might PM you someday about coming over and using yours when I get some time off!

FYI......I have sundays and wednesdays off.

[BA80]

So you can only adjust each carb to the other ones, but not a pair? Don't know if that's a good idea or not, when I take the time to do mine, I want them to be correct. I guess for a baseline to get you up and running it would be okay.

Read what I wrote in post #12 or you can just go to the manual, it'll say the same thing.

A pair (1 & 2) another pair (3 & 4) and then a pair of pairs (1 & 2 to 3 & 4)

[debauchery]

i'm more confused then when i started reading this thread

[crazy steve]

HUH? There are only 3 adjustments for the sync on a set of carbs.

You cant adjust INDIVIDUAL carbs that way. 1 & 2 need to be adjusted to match with a SINGLE adjusting screw between them, and then 3 & 4 the same way and then with the adjusting screw between 2 & 3 bring the two pairs together to match...

Whaaa?

Let's see...

Adjustment 1: adjust 2 to 3.
Adjustment 2: adjust 4 to 3. 2, 3, and 4 will now all be the same.
Adjustment 3: adjust 1 to 2, 3, 4 (see 2).

Explain to me why that won't work... and don't say 'because the FSM says so'..

DaVinci is correct that if/when you adjust the idle mixture, all the readings will change slightly, but that will be the case no matter what order you adjust in. I'll also point out that as the individual cylinders are adjusted (or pairs, as the case may be), that will change the 'load' the others see and slightly change their readings also, with the differences becoming smaller as they get closer to each other. And yes, a single-gauge set-up will take slightly longer to use, but will accomplish the same results... for less money.

[natemoen]

I guess either way, steves or gregs, does the same just a different order

[ManagerMike]

Here's the one I made from an expired fire extinguisher. Works great and looks cool as hell!

[motoman]

Sorry all....Greg has it correct, and in correct order.........can't adjust individually...

[BA80]

Steve's way will work, now that he explained it better, it's just kinda like going around to the back door even if the front door is easier to get to.

Although, that would probably be the best way to do it with a single guage now that I think about it a bit. Not very accurate in my opinion but the most logical.

[DGXSER]

If your using four gages, just make sure they are all four reading equal to start with...calibrated. To do that, read all four off the same cylinder and mark for any derivation in each. I would re-calibrate at least semi-annually. The folks I know who have used four gages in the past have always found they were off at least a little every time they checked them.

I personally use a single gage and no aquarium valve, just swap my hose from one cylinder to another, moving and replacing vac caps as I go, no calibration needed. I typically start with 1 and 2. I read 1, say it is at 9.5" of vac. Then I read 2 and maybe it is at 11", I then adjust the synch screw so 2 is about 10.25" Then I recheck 1 and make any fine adjustment. Repeat on 3 and 4, maybe that pair ends up at 11.25" vac. Well then I hook my vac gage to 2 and adjust till it is roughly 10.75", check each again, and fine adjust. then go back through and verify they are all about the same. Is it longer than having four gages hooked up? Don't know, never used four gages. But it certainly does not make a 10 minute job an hour long job, maybe a 20 minute job into a 30 minute job.

And yes, you then should tune your mixture, and then repeat the synch.

Another little reality is that is makes no difference if you start on 3 & 4, or 1 & 2. In the end, your still adjusting 1 against 2, and 4 against 3. and then adjust the pairs to match.

The position of opening of the #3 throttle plate is set by the main idle screw, and then the synch screws adjust the throttle plates of the adjacent carbs to the one next to it. But all the vacuum levels, including #3 change as you synch the carbs together. Meaning, you could read the vacuum on 3 before you touch a screw and it might be 10.25", and when your done it might be 9" or 12" or anything n between even though you never touched the idle screw and therefore did not alter the amount of opening on #3 throttle plate.

[BA80]

I use a 4 guage setup and check the calibration regularly with a vacuum pump.

I also have the "aquarium" valves that came with it so I can read it accurately.

Tuned the mixture adjustment and synced the carbs in about 10 minutes this afternoon.

It hadn't moved a lot since last fall............smooth as silk.


Last trip............40MPG..........125.....130 top end.