Spark plus Gurs, Please??

[GeeBee1]

Dale:

Drive it like you stole it, its about time.

 

[Tinster]

For frequent checking of a carbs mixture, it's recommended, and not just by me, to raise the air valve about 1/8 of an inch and observe the engine speed response.

Try as I might- I've not acquired that listening skill.

d

 

[poolboy]

Dale, you get that engine to idle somewhere between 800 and 1000 and lift the air valve an eighth of an inch with a slender screwdriver without blocking the air with your hand and I guarantee you the engine speed will change.
If there is only a slight change then you are pretty darn close to having the mixture correct.
You get immediate results from your test without having to drive a 100 miles to evaluate deposits on your plugs.
Just play with it until you are able to distinguish the symptoms.
Then again, if you have the mixture right, right now, don't expect the difference to be all that great.
I mean that's the way it's done unless you have access to some kind of CO meter that you can put in the exhaust pipe.
An aid that is more visual, however, is a Vacuum Gauge connected to the intake manifold where your brake servo connects.
Maximun vacuum there gets you pretty darn close. The Vacuum gauge there will also help you find your ignition timing sweet spot by indicating maximum vacuum as you rotate the Dizzy.
If your engine is in good shape 17 to 20 in-Hg is the operating range you would be looking for for both adjustments. Try it, you'll like it.

 

[Tinster]

Poolboy: you wrote:

An aid that is more visual, however, is a Vacuum Gauge connected to the intake manifold where your brake servo connects.
Maximun vacuum there gets you pretty darn close. The Vacuum gauge there will also help you find your ignition timing sweet spot by indicating maximum vacuum as you rotate the Dizzy.
If your engine is in good shape 17 to 20 in-Hg is the operating range you would be looking for for both adjustments. Try it, you'll like it.

<span style="color: #990000">Huuum? I ran that test last weekend.
I got a real constant 21 in Hg

good info to know. I thought the test was for determining vacuum leaks.

d</span>

 

[martx-5]

...

<span style="color: #990000">... I thought the test was for determining vacuum leaks.

d</span>

Dale, here's an article on interpreting the readings on a vacuum gauge. It's incredible the amount of information you can get from such a simple instrument.

 

[poolboy]

<span style="color: #990000">Huuum? I ran that test last weekend.
I got a real constant 21 in Hg

good info to know. I thought the test was for determining vacuum leaks.

d</span>

Given that, I'd say your engine is darn near if not perfectly tuned.
Not saying you won't have a condensor or rotor fail, but as far as tuning, I'd say you've found that "sweet spot".