Thermoquad help - primary overfueled, boiling over on shutdown

[Someotherguy]

if you dont have a gram scale, harbor freight sells one for like $12...

 

[Secret Chimp]

Well these brass things of mine weigh 10.5, but if you look at my first post you'll see they float with a good 2/3s submerged. Is that normal?

 

[Meep-Meep]

Another thing to check for is side to side clearance. If the float gets hung up before it closes the needle and seat then you will have flooding.

I want to say Carter used brass floats on TQ's early on but can't swear to it. Maybe I'm thinking of something else.

A scale is the only way to check floats.

In the 60's Ford actually published a fuel level for the Autolite 4100 carbs, but those you can run with the air horn off (kind of neat actually). I recall setting the float to spec and measuring the fuel level and it wasn't even close. This was in the 80's and the gas was already different so I'm wondering if the specific gravity of the fuel changed. Something to think about anyway.

 

[Someotherguy]

I still say to try the old foam floats.....

 

[RustyRatRod]

Another thing....SOME Thermoquad floats are side specific. They cannot change from right to left. They started making them interchangable somewhere along the way. You might want to look for that too.

 

[Secret Chimp]

I only now realized there are two completely different Meeppeople here.

 

[Someotherguy]

yeah, thats my bad, i wasnt aware their was a meep meep already here

 

[Secret Chimp]

Another thing to check for is side to side clearance. If the float gets hung up before it closes the needle and seat then you will have flooding.

I want to say Carter used brass floats on TQ's early on but can't swear to it. Maybe I'm thinking of something else.

A scale is the only way to check floats.

In the 60's Ford actually published a fuel level for the Autolite 4100 carbs, but those you can run with the air horn off (kind of neat actually). I recall setting the float to spec and measuring the fuel level and it wasn't even close. This was in the 80's and the gas was already different so I'm wondering if the specific gravity of the fuel changed. Something to think about anyway.

TQs did start off with brass floats, but they were foam for a majority of their variations.

As for the fuel level check, that's interesting. My foam floats sat pretty low as well, I just figured they'd become saturated. Maybe everything floats less in this stuff vs the fuel used for specs 30-40 years ago. I think I might try adding enough height to the factory specs to approximate where the fuel level would be if the floats sat, say, 1/4 submerged instead of 2/3 to 3/4 as I imagine was closer to the original design.

I'll also check to see if the sides are scraping - I hear some brassy noises whenever I take the air horn off, but I hadn't looked to see. I figured the float drop on these things is so ridiculous that it was just the floats scraping the bottom of the body.

 

[67 coronet]

i know everyone is talking float levels,but have you checked for any cracks in the mainbody that will feed fuel with the needle and seat shut off?cracks could also explain your side to side varience in veturi flow.see if you can wedge the floats,or something else,in a way that shuts off the needle and seat and then put fuel presure to the feed point with your small pump to see if fuel is getting into the carb.

 

[Secret Chimp]

There's no way for fuel to get into the carb outside of the needles and seat areas short of a hole in the rear of the air horn casting, unless I'm misunderstanding what you're saying. The fuel level in there will hold at idle seemingly indefinitely, it's just way too high. It isn't filling up and spilling over and filling up again. I may have had an issue like that before but I'm pretty confident fuel supply is under control now. If I was adventurous I'd drill and thread a sight plug in the side of the body or on top of the air horn, but I'm on the other side of the globe from being skilled with fabrication and modification.

 

[67 coronet]

you can also fill the bowls with dyed water and let sit overnight on white paper to see if any leaks out.also a good way to check for leaks.

 

[Secret Chimp]

There's a good idear.

 

[Meep-Meep]

I only now realized there are two completely different Meeppeople here.

Yep. I've been cloned!

 

[Someotherguy]

 

[Secret Chimp]

OK, I give up for now. I set the floats down another 1/2 inch and it still leaks gas from somewhere on the passenger side on shutdown, yet it runs out of gas on hard acceleration. Did I overshoot my float level, is it fuel pressure, maybe, I have no idea. I've wasted a good week and a half on this thing. It doesn't work on factory specs and everyone else's seems to, brass floats or not. I just want to drive my dang car for awhile.

 

[67 coronet]

just get an edlebrok and go.some times you gotta just say"is it worth the hassle and head aches!".

 

[Someotherguy]

just hop on ebay and buy you a fresh rebuilt tq...i think i seen a few on there the other day for under $150....

 

[Secret Chimp]

This one was supposed to be "a good runner" but I found out afterwards the guy only had it idling on the donor car for a few minutes. The first "rebuilt" one I found on eBay looked like it had been sprayed with aluminum spray paint to make it look better (I found the same paint inside of some of the gaskets on this TQ) so who knows how well it actually works.

The next time I foray into TQs I'll want to buy from somebody local so I can try the thing on my car before I buy it.

 

[Secret Chimp]

Well in a surprise turn I saw that Demonsizzler is back from his hiatus when he posted a 340 TQ for sale over on Moparts. Long story short I'm going to send this carb to him to figure out.

When checking out the jet numbers, though, I did find that the driver's side jet was barely tightened down. No more fiddling though! David can fix it...

 

[RustyRatRod]

Yeah David is a good guy. He'll get it straight.