Hey folks

I just put a thermoquad on my 318 about a month ago, and i cant seem to get this bog at WOT tuned out of it :0/

I adjusted the secondary door up pretty tight, still does it, but i dont think the issue is with the secondaries, because i can hold the secondary door shut and it will still bog out when i blip the throttle to WOT...I think maybe the pump shot isn't good enough for wot...i have a video down below of it doing it...

Click image for video....

I'd check for an immediate and healthy duration squirt starting as soon as you tap the throttle. Correct float level and no vacuum leaks. When you changed carbs you went from ported vacuum advance on the old carb to ported vacuum adv on the TQ correct?

Pull top of carb and replace accl pump. Sure sound dead to me

From my vantage point, it looks like your linkage is all screwed up. Is that the choke pull off I'm seeing on the drivers side of the carb?

The choke has to be functioning correctly or blocked out for the secondaries to work.

Got any GOOD pictures showing both sides of your carb?

Here's a crappy pic of the TQ on my wagon, see the choke pull off?



If its on the drivers side, what the heck do you have it hooked up to?

The linkage isn't the correct mopar linkage, i believe it's a tq from a 79-80 international scout...it has another vacuum pot on the passenger side for the secondary flap...I'm not sure what the drivers side vac pot controls...it is hooked to a vacuum source though..

Hmmmm...alrighty then. Having only worked on Chrysler spec TQ's, I've never seen that before.

You've got me curious now as to how it hooks up, and how its supposed to function.

I still think that some of your problem may be related to this.

this is the only info i could find on the d-side vacuum pot..it's supposedly called a "delayed diaphragm"

The accelerator nozzles look ok; how high does the accelerator pump stem stick out above the top casting? It should be about 1/2". Also one little known trick to get the 2ndary to function properly is to:

crank the engine, and with your air cleaner off, push down on one of the two 2ndary air door dimples and:

if the air door does not have enough 'slack', you can not adjust the bog out of the 2ndaries. This means that if the air door rear is too tight against the top casting stop, you will need to bend the rear crook of the 2ndary air door linkage that attaches to the pull-off.

Just remove the rear linkage e-clip, carefully, and bend the rear crook backward just a bit and install the linkage(leaving the rear clip off)and fire the engine and check the air door slack again, for about .200" movement before you have tension.

Let me know if this helps, David.

Pic of the pull-off linkage and where to bend it:

And all you ever need to know.

http://www.carbkitsource.com/carbs/tech/Carter/pages/tqguide-Vaanth.html

As i said prior, when i blip the throttle, it will still bog completely out even if i hold the secondary door closed, it's not a secondary bog issue...it's a primary bog issue...

in the driveway, and on the road i can ease into the gas, then stab throttle and she will fly like the wind..The only issue is a off idle bog..

You said in your post you had a wot bog. I was watching the video and it was only bogging at wot; was not bogging when you only opened the primaries. Also it looks as if your air door spring tension is too loose. You have to loosen the air door spring lock collar and carefully take the tension(you likely know this but others may not)and let the air door rear drop down. Then start turning the adjuster slot ccw with the lock collar still loose, and then when the air door rear is against the top casting stop, turn ccw until you have 1.5 turns and lock the collar.

You may have two separate circuit problems, one on the primaries and one on the 2ndaries. Fix one at a time.

Did you check these things that were suggested by us?

If you can close down the choke flap some, partly etc with the engine running and at normal operating temp and the engine idles without stalling(in park), then yes, you have a lean condition. Now that would be on the idle circuit. Primary jetting is not a factor until you move the throttle far enough to shut off the idle circuit. So if you get a bog or hesitation while slowly moving the throttle, then that would be a tell-tale sign of too small a primary jet. As for holding the air door shut while you hit the throttle(assuming you open the 2ndaries any at all, then you will get a bog because you are pulling in more air and no gas in the 2ndaries. The 2ndaries are cut on by the 2ndary air door dimples approaching the 2ndary spray bars. The dimples create a venturi effect and thus pull gas from the spray bars.

If your carb has smaller than .098" primaries and the carb is an IH 850 cfm you will need the .098" id jets. I think your carb is a 9127 or 9128? The number is stamped on the driver rear corner of the base plate facing the firewall. The number is stamped on the top flat of the jet; for example, 4098 is a .098" pri jet. The jetting is very lean on the IH carbs compared to A Mopar 850. 2ndary jetting is lean too at .110" but should be at least .125" id's and the number is stamped on the outside, example 5125. On the primary side, I would suggest that you close down the choke flap about 1/3 or 1/4 closed by hand and open the throttle slowly staying only on the primaries and if the bog goes away, the primary jetting is definitely too small.


So you may have to check these jet numbers to be sure, David.

If that pump shot from the 2nd vid was after the bowls are full (such as when the car has been started for a minute) then it is WAY TOO WEAK!!! It should shoot a steady hard stream, kind like when you turn a spray bolt nozzle to jet. It should really shoot and not be airy until the very end of the shot.

Do you really have pump the carb a lot in the morning to get it to start?

It looks like the pump shot was shooting a lot of air, which leads me to believe it might be the connecting plastic tube, or the pump leather/plastic lip is shrunk and not pushing fuel.

Your first video is the classic example of lean spot when you hit the throttle, meaning bad pump shot. Can you really slowly open the throttle and it pick up just fine? If so this is another classic symptom.

Also welcome back Demonsizzler!

David:

It is a 9128....It does like to said, moving the throttle slowly to wot, it runs fine, if i partially close the primary choke and blip the throttle to wot, it works great..the only issue is a wot run with normal choke door operation(open)...I dont think it's a jetting issue, the carb came off a 345ci international scout...should be plenty enough carb for a 318..

Kilroy:

yes it does take forever to get it started when cold...and yes, it runs great as long as i ease into the throttle...

I think i'm gonna replace the pump plunger, and take a look at the transfer tube also...thanks for the tip on that

I think your on it, let us know!