Fast cam setting idle on a thermoquad

Hi all, I've got a TQ that has two vacuum pulloffs, the one on the side of the (electric in my case) choke setting and another on the other side where all the fast idle cam and rod are. It's fully restored and after adjusting air door, choke kick and other settings, is going beautifully but for one thing. I'm no expert but I am a mechanic and have been trying to understand how to get these great old carbs running right. I know how to engage the choke for cold starts and that works fine. After going to the floor with the accelerator, slowly release so the fast idle screw rests atop the fast idle cam. All good. But my fast idle screw always ends up right at the end of the first step, as in, the highest speed setting, just near the drop to the second step. I can't get it to end up coming to rest on the second step, just before the step up to the highest first step. Consequently, or maybe its for a different reason, if I set the fast idle to say, 1300 RPM (auto trans), it starts fine but the slightest touch of the throttle drops it down and stalling on a cold morning is a problem. What am I missing here? Cheers and thanks in advance to anyone who has some thoughts on it.

Comments. I am in Sydney & have worked on these carbs since the 70s. I remove ALL the choke mechanism, not needed in our mild climate. The triple booster primaries do not need a choke.

- The Ford TQs had some ridiculously small sec jets, some were 0.098", smaller than the primaries!!
- Get rid of the restrictive Ford fuel filter & replace with a Ryco or similar in line paper filter.
- The factory spec for the air valve spring is usually 1 1/4 turns. I watched a TQ on the dyno earlier this week that was set at 1 1/2 turns & it had a power dip. Set it to 2 1/4 turns, dip was gone.
- Enlarge the sec jets to 0.125" [ 1/8" ].
- Removing the elec choke housing will leave a vac port exposed; be sure to plug it.

The rod connecting the cam is the usual adjustment point. Bend it to raise the screw up higher on the cam. A service manual would show the exact area to bend. I have never seen a TQ on a Ford or with 2 pull-offs. Of course I've never been to Australia!
Mike

Geoff 2 said:

Comments. I am in Sydney & have worked on these carbs since the 70s. I remove ALL the choke mechanism, not needed in our mild climate. The triple booster primaries do not need a choke.

- The Ford TQs had some ridiculously small sec jets, some were 0.098", smaller than the primaries!!
- Get rid of the restrictive Ford fuel filter & replace with a Ryco or similar in line paper filter.
- The factory spec for the air valve spring is usually 1 1/4 turns. I watched a TQ on the dyno earlier this week that was set at 1 1/2 turns & it had a power dip. Set it to 2 1/4 turns, dip was gone.
- Enlarge the sec jets to 0.125" [ 1/8" ].
- Removing the elec choke housing will leave a vac port exposed; be sure to plug it.

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Thanks Geoff! I had a lean bog in the early days and back then adjusted the spring tension on the air door until it went away. I was going a quarter turn on each occasion then take it for a run to see if was was gone. It finally disappeared and by then I had ended up somewhere over 2 full turns. I will get rid of that metal filter as I have some good inline ones in there already. I wasn't aware of the jets issue so I'll look into that. I kind of like the choke as it is a bit of a pig and requires holding the revs up manually until it warms up to avoid stalling when cold during winter. I would like to get rid of it though. I probably need a stall converter (stock C6) to deal with that because it has a slightly higher lift (not sure exactly) cam in it but the heads are stock 2v (ran out of funds on the build). I'd love to do some work on the heads or swap them out as I think they are the part of the equation that is holding her back. Thanks again for your advice. Dan

493 Mike said:

The rod connecting the cam is the usual adjustment point. Bend it to raise the screw up higher on the cam. A service manual would show the exact area to bend. I have never seen a TQ on a Ford or with 2 pull-offs. Of course I've never been to Australia!
Mike

Click to expand...

Brilliant thanks Mike!!! I wondered if it was that rod as it is described in the manual as the one for adjusting the gap between the lower edge of the choke blade and the air horn wall. I'll take a look at the point of adjustment (usually an elbow in the rod) as described in the manual and have a play with it until I get the fast idle screw landing on that second step near where it transitions up to the highest first step. I'll post a reply so its here on the forum for anyone else who might come across this issue. Thanks again!! Dan

493 Mike said:

The rod connecting the cam is the usual adjustment point. Bend it to raise the screw up higher on the cam. A service manual would show the exact area to bend. I have never seen a TQ on a Ford or with 2 pull-offs. Of course I've never been to Australia!
Mike

Click to expand...

I should add - whilst this one is a Ford, my other car is a 68 Charger. I would like a TQ on it too if I can find a decent 440. Cheers, Dan

Dan PM me. The Ford TQs are just as good as the Chrys TQs when modified. If you get a Ford TQ, I will modify it free of charge for you. I was present when earlier this week when a 440 engine that I built went on the dyno. It made 600 hp with a modified 850 TQ. The TQs flow more than advertised.

Pratty said:

Brilliant thanks Mike!!! I wondered if it was that rod as it is described in the manual as the one for adjusting the gap between the lower edge of the choke blade and the air horn wall. I'll take a look at the point of adjustment (usually an elbow in the rod) as described in the manual and have a play with it until I get the fast idle screw landing on that second step near where it transitions up to the highest first step. I'll post a reply so its here on the forum for anyone else who might come across this issue. Thanks again!! Dan

Click to expand...

Pratty said:

Thanks Geoff! I had a lean bog in the early days and back then adjusted the spring tension on the air door until it went away. I was going a quarter turn on each occasion then take it for a run to see if was was gone. It finally disappeared and by then I had ended up somewhere over 2 full turns. I will get rid of that metal filter as I have some good inline ones in there already. I wasn't aware of the jets issue so I'll look into that. I kind of like the choke as it is a bit of a pig and requires holding the revs up manually until it warms up to avoid stalling when cold during winter. I would like to get rid of it though. I probably need a stall converter (stock C6) to deal with that because it has a slightly higher lift (not sure exactly) cam in it but the heads are stock 2v (ran out of funds on the build). I'd love to do some work on the heads or swap them out as I think they are the part of the equation that is holding her back. Thanks again for your advice. Dan

Click to expand...

Update- Geoff, you were're absolutely right. I bent the rod for the fast idle cam and that allowed the cam to rotate a bit more so as to ensure the fast idle screw cam to rest at the edge of the second step just before it goes up to the highest first step. It was easy or and I actually found it easier to remove the rod and measure. I got it in the prefect spot after a few votes at it. All I had to do then was re-adjust the choke valve kick setting on the other side as it had moved as a result of that adjustment to the fast idle cam rod. Thanks again Geoff! Dan