My 318 dyno results
I have checked the choke, it "works". Only the working time of the choke is adjustable.
That's not exactly true Olei
You also have an adjustment on how far the choke opens right after start-up. This is called the vacuum break. To change it, you have to bend the link-rod.
The trick is to have the choke set so that after it starts, you don't have to do anything for about a half a minute. Then as the rpm begins to rise, you tap the pedal to allow the fast idle cam to drop down a step or two. Then you can drive away.
If you have to keep slapping the pedal to keep it running, then you may have several problems, chief of which is probably insufficient timing, due to a non-working vacuum advance; and second would be the vacuum-break adjustment. Now you only have a few seconds at start-up to get that vacuum break set-right, so don't be discouraged if it takes a half a dozen attempts, or more.
And of course, when the engine is stone-cold, that choke has to be completely closed. Part way won't do it.Almost closed won't do it. It has to be completely closed, and the secondaries also have to be completely closed.
During the first few revolutions, the engine will be attempting to start on the fuel you pumped in there, by the pedal. And it will be trying to get air from wherever it can,namely; the PCV, around the perimeter of the choke-blade, past the secondary valves,and from the float bowl, through every orifice that is open, like the MJs, the PV,the low-speed circuits, and the bleeds; every orifice under that closed choke will be gushing gas, except the accelerator pump.
>As soon as the engine fires, and even slightly before, manifold vacuum will begin tugging on the choke pull-off. And that will reduce the pull on all those bleeding fuel ports. As the engine catches, the choke blade opens to whatever you have adjusted it to, and if you got it right, the engine will begin to slowly rev up.
If you got it too far open, the engine will begin to run out of fuel, and slow down, causing you to slap the pedal to keep it running. This will then kick down the fast idle cam, and now yer stuck there babysitting the thing. If it stalls, a couple of shots from the accelerator pump and it will start right up, only to repeat this crap.
If you got it to far closed, then engine will very-soon begin to slowdown, and you will again have to help it stay running. But the fast idle cam will at least still be there for you. A very rich engine takes a long,long, time to warm up. If it stalls, it will be very difficult to restart.
If you get it just right, the engine will catch, and begin to slowly rev up as the engine warms up. In about a minute you will find the rpm objectionable and you will tap it down. Then it will run just nicely for another period of time, which is governed by the choke spring, and that you have the power to adjust for your local temperature, and to match the characteristics of your engine.
>With aluminum heads,during the time that the engine is on the tapped-down fast-idle step, it is very important to have a working VA kicking in a bunch of timing. Without it, the fire doesn't get going until the pistons are way down the bore, and the engine barely has enough power to idle, much less take being put into gear.
Now, you have set the idle timing to 20* which is about half of what it wants. And I have no idea of what your timing might be at the warm-up idle-speed, But The VA, together with the centrifugal,have to kick in the rest.
>After the T-port sync has been set, you may find the idle-timing down at say 12*. Well this is gonna make big trouble on the choke system. Now it will be more important than ever, to have a good working VA, AND THE BIGGEST ONE YOU CAN FIND,usually about 22*. And that is also why I recommended the 2-stage timing curve.
If you can't get the VA to work off the sparkport, while the engine is on the fast idle, you will have to hook it directly to manifold vacuum. This may introduce a new set of issues, namely a too-fast idlespeed. But those are usually easier to overcome than a crappy warm-up period due to insufficient timing.
> Once you have the idle timing set, you will have to revisit your power-timing.
Oh CheezeWhiz , I'm late to the party,lol.