Idle problem on C15 261 CU IN

[Bob Carriere]

Hi Terry

How steady is the reading at 18 inches........?

If she is steady but looses vacuum slowly as you lower the idling speed..... you may have a small air leak that is easily overcomed by more rpm..... now a small leak may be hard to find but an un-ignited propane torch or a spray can of ether should work.......

You say that moving the distributor by hand did not affect the vacuum reading?? It should make it stumble in either direction and you aim for a middle point..... then drive it ... if it pings or stumble it needs to be either retarded or advanced slightly...... I now use the vacuum gauge to set the timing.

Now the idle mixture screw ...... have you played with that yet......

How are you controlling the engine speed right now.... do you have a manual throttle cable installed yet????

Try setting the rpm at around 800 then go in and out no more than a full turn on the mixture screw and watch the vacuum gauge.... aim for the highest reading..... slow the rpm down a notch to 700 rpm using the idle screw on the bell crank and repeat the process.....

You may have to find and cure the leak before the final adjustments.

Don't quit now you are so close.....

.... at worst stay up late Xmas night and ask Santa for advice.

We did our home Xmas yesterday as we are travelling to the inlaws on Xmas eve on the far side of Toronto.... so already all turkeyed out.

All the Best for the NEW YEAR and a very Merry Xmas to finish 2016.

Bob C