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TQ weirdness - one booster leaking/overfueled, one not?

Posted By: Secret Chimp

TQ weirdness - one booster leaking/overfueled, one not? - 08/02/12 06:32 AM

I'm about to see if all weirdness goes away tomorrow, but I'm waiting for the JB weld to cure (wells). Wanted your take before I fire over again.

Long story short, my Thermoquad has been constantly flooding since I got it. It's also acted inconsistently side to side in the primary venturis.

I installed brass floats today, it still floods. I took a closer look and found that the tangs on the end are hitting the needles at more like a 60 degree angle rather than parallel (bent and fixed that) and found that if the float arms flex the ends would hit some overhang on the gasket first (notched those out, same problem as the old one I replaced and never noticed). I have no idea if this will work but if it still floods afterwards I'm going to JB Weld the dang seats to the air horn.

It also have some throttle shaft vacuum leak slop that I'm leaving alone for right now (if I push back against the throttle the right way my idle drops noticeably)

Blah blah blah, the driver's side venturi keeps seeming to get way too much gas for some reason compared to the passenger side. The jets appear to be the same, the rods are the same, and the tree has no problem going up and down and seats fully when the car is idling. Above a certain idle speed, I can see gas welling up in the little tube that feeds the venturi. If I start manually cracking the throttle open, it starts dribbling out. If I get it up higher, it gets worse to the point where it's a white spray of fuel at no load and maybe 1400 rpm. The passenger side doesn't show any signs of doing anything like this.

I've poked wire into all of the air bleeds and tube thingies that surround that area and nothing seems to be blocked.

What could be causing this? Yes, the o-rings are in place in the main body, the floats are set at just over an inch with the gasket on. I've covered the basics. It's been doing this in some form or fashion since I got it, pre and post rebuild.
Posted By: RapidRobert

Re: TQ weirdness - one booster leaking/overfueled, one not? - 08/02/12 03:07 PM

Keeping it simple I'd change out the needle/seat on the leaking one & double check there's no more of the interference you mentioned. The float ain't saturated correct? EDIT missed that you have new brass floats
Posted By: Secret Chimp

Re: TQ weirdness - one booster leaking/overfueled, one not? - 08/02/12 09:48 PM

Still flooded! I'm wondering if I'm adjusting the floats incorrectly. The manual says from the "toe end" and I'd been doing it from the highest point on the float. The toe ends on the floats are another 1/3 of an inch lower than the rest of them, i.e. my float setting was something like 2/3 of an inch if you're supposed to do it from the toe end.

I'm taking a break from flooding my poor engine and poor nose with gas, but I've reset the floats to 1 1/16 on the toes. I tested the needles and seats off of the car and they hold just fine even with just the floats' own weight against them (I used a bike pump after I found I can only generate like 1.5 psi with my own lungs :P) Hopefully that's my problem. I certainly understand why lesser folk just start throwing these things against the wall after a few tries though...
Posted By: meep_meep

Re: TQ weirdness - one booster leaking/overfueled, one not? - 08/02/12 09:58 PM

this is where you are supposed to measure from...



I just fixed a lean issue with my TQ, popped the top off and found the floats set waaay too low in the bowl..

Google hits came up with 27/32nds and 29/32nds as the correct float height...i went with the higher 29/32nds #....it works fine now...

I'm pretty sure that a 2/3 of an inch setting would cause a flooding issue...
Posted By: Secret Chimp

Re: TQ weirdness - one booster leaking/overfueled, one not? - 08/02/12 11:46 PM

Shoot, based on that I definitely had my floats set too high the last time I tried running it. The float arms were almost parallel with the cover.
Posted By: Secret Chimp

Re: TQ weirdness - one booster leaking/overfueled, one not? - 08/03/12 01:39 AM

OK, now I'm stumped. It's still flooding. The last thing I can think of is the needles hanging up or coming too far out for the fuel flow from the float drop. However, I haven't read how to set the float drop on these things nor can I figure out by looking. The floats hang down WAY low right now, well over an inch and a half or to some point where they'd just be sitting on the bottom of the body if there was no fuel in it. Unless my gauge is completely wrong my fuel pressure's only at 3psi.
Posted By: RapidRobert

Re: TQ weirdness - one booster leaking/overfueled, one not? - 08/03/12 01:46 AM

bad needle/seat. float set too high. alot of minute debris in the fuel. interference in its travel. maybe there's a different ruler setting for brass rather than nitrofill type floats
Posted By: Secret Chimp

Re: TQ weirdness - one booster leaking/overfueled, one not? - 08/03/12 02:05 AM

I got these floats off of quadrajetparts.com: http://quadrajetparts.com/carter-thermo-quad-parts-thermo-quad-floats-brass-float-oem-249-p-937.html

I haven't figured out if there's a different setting from them vs 1 inch.
Posted By: Secret Chimp

Re: TQ weirdness - one booster leaking/overfueled, one not? - 08/03/12 05:48 AM

I about give up on this thing. It's not flooding out, but at 29/32, 1 1/4, it still fills up too much. The level's getting high enough to where it will bubble over and drip out of the passenger side throttle shaft opening after I shut it off. Gas starts welling into the primary bores and fogging up.

The driver's side primary keeps getting way too much fuel. I can see gas welling up around the driver's side metering rod if I leave the covers off while it's running, and after the carb has filled up I can barely crack the throttle and it starts spraying fuel in like a garden hose. I adjusted the tree to 1.5 turns off of when the piston just started moving, no difference. Seating both idle screws won't kill it.

I know the needle and seats are fine, I pressurized it with a bike pump on the bench again up to like 10 psi and they held. I have my fuel pressure at just under 3 psi.

It isn't loading up the primary bores any more, but the thing just runs way too rich. I think the gas I'm seeing at the rear is from the spray from the needles hitting the already-saturated-from-flooding top gasket. I've let it idle for awhile and it's stinky but it will keep running. New nitrophyl floats weighed 8 grams, these things weigh 10.5. But I've set the float level over any factory spec and it still acts this way. The hell is wrong with this thing? I'm about ready to give up and go back to my cold-stumbly Carter AVS. It only gets 14 mpg but at least it works.
Posted By: Secret Chimp

Re: TQ weirdness - one booster leaking/overfueled, one not? - 08/03/12 07:39 AM

No idea if this helps, but I plugged the jet with a float pin wrapped in scotch tape and filled up the driver side bowl to see how these floats float. The fuel level with the float in there was just lapping up the very rear step on the body.

http://imgur.com/hcexP

Buoyancy level for the float (upper squiggle on the left side, I messed up)

http://imgur.com/Gx4TE

Any idea if this warrants different float settings?

ALSO (I know I write too much)

I've read that gas will find its way out to the main venturis if any of the vents are plugged up. I'm wondering if this is why I've kept getting weird behavior out of the driver's side venturi - seeing gas wick up the metering rod and it seeming to be overfed.

I've poked pretty deep in all of the holes I can find, but I don't really know what I've poked (said the drunk in the brothel the next morning).

How can I check and see if maybe the driver's vents are plugged up completely or intermittently? I'm not sure which tubes are which.
Posted By: Rug_Trucker

Re: TQ weirdness - one booster leaking/overfueled, one not? - 08/04/12 05:32 PM

You know you measure the float height from the top with the gasket on there? You measure from the gasket.

Did you download this? http://www.imperialclub.com/Articles/ThermoQuad/index.htm
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