Thermo Quad Floods Over Help

Posted by: moparpoolman

Thermo Quad Floods Over Help - 03/05/18 06:08 PM

On a 72 400 my Thermo Quad floods over after the car is turned off. I just replaced the needle and seats and made sure the floats were at the right adjustment. Started it up, ran great, ran it for a while, got it up to temp, turned it off and in about a minute it starts flooding over again. I can see it dripping in the primarys and it drips out the primary throttle shaft on the passenger side. Am I missing something? Anyone else have this problem? Possible solutions? Thanks
Posted by: amxautox

Re: Thermo Quad Floods Over Help - 03/05/18 06:10 PM

What is the fuel pressure from the pump?
Posted by: moparpoolman

Re: Thermo Quad Floods Over Help - 03/05/18 06:16 PM

Not sure, I'll have to check that, think its a stock mechanical pump though
Posted by: John_Kunkel

Re: Thermo Quad Floods Over Help - 03/05/18 06:31 PM

Main body warped or cracked.
Posted by: dynorad

Re: Thermo Quad Floods Over Help - 03/05/18 06:54 PM

It sounds like the fuel is boiling in the bowls. If you have vertical space you might consider a thermoplastic carb spacer and a heat shield.
Posted by: BLACKHEMIRR

Re: Thermo Quad Floods Over Help - 03/05/18 07:09 PM

If you run it and shut it off while it's cold, does it overflow? If not, you might be able to rule out fuel pressure and look more at heat related causes. However, I think the Thermoquads have a pretty large bowl vent, so it's hard to believe the bowls could be pressurizing (from fuel vaporizing) and forcing fuel out when you shut it off. Just a thought.
Posted by: BLACKHEMIRR

Re: Thermo Quad Floods Over Help - 03/05/18 07:17 PM

Oops. Dynorad beat me to it. Sorry
Posted by: 500ciDuster

Re: Thermo Quad Floods Over Help - 03/05/18 07:21 PM

both styles of floats can sink after years of use, with brass you can usually feel gas sloshing inside. The wells will leak after years also and I've had good luck using JB weld to glue them back on
Posted by: ScottSmith_Harms

Re: Thermo Quad Floods Over Help - 03/05/18 09:19 PM

Yep, my guess is a bad float or a bad float adjustment.
Posted by: moparpoolman

Re: Thermo Quad Floods Over Help - 03/06/18 07:41 PM

Thank you for the thoughts thus far. This is where I am now.

does it with engine cold or hot
has about 4-5 psi fuel pressure
floats and float levels are good
tested needle and seats and they are good
plastic body not cracked or warped
epoxied jet bowls are good, no leaks

could the gaskets / o-rings for the 2 aluminum tubes from the upper aluminum top that seal next to the jets in the plastic body cause flooding over??
Posted by: 500ciDuster

Re: Thermo Quad Floods Over Help - 03/06/18 08:20 PM

That was something that I forgot to mention and should be looked at, they get compressed and don't work like they should over time
Posted by: RTSrunner

Re: Thermo Quad Floods Over Help - 03/06/18 08:28 PM

The O-rings at the base of the bowl like mentioned above(I had one fall out or missed on install once,had a little fire!) Possibly try lowering the float level a tiny bit from spec it may help.
Posted by: ScottSmith_Harms

Re: Thermo Quad Floods Over Help - 03/06/18 10:25 PM

BTW, those O-rings should be square shouldered (look like a tiny slice of rubber hose). Round O-rings (found in some rebuild kits) can sometimes leak.
Posted by: moparpoolman

Re: Thermo Quad Floods Over Help - 03/08/18 06:28 PM

Seems to be the o-ring seals, changed them and not flooding over any more. Thanks