The top of my Thermoquad after shutting the engine down is ridiculously HOT

[8v-of-fury]

After shutting down and sitting about an hour in an ambient of 72-80F, with the sun down even, the top case of my Thermoquad was an infrared thermometer verified 130F and was physically too hot to hold your hand to.

Now, if the car is driven as it should be and then put to sit for a day or two.. the car will not start the next time without excessive cranking and pumping. Is this vapor lock in the line? or is the fuel boiling out of the bowl?

This is why I am looking for sources on a 1" wood/phenolic spacer that is 850cfm Thermoquad acceptable with the bigger primaries.

 

[jasperjacko]

130 degrees is nothing, that is called heat soak. It would be hotter without the plastic bowl. If your float bowl is going dry, it could be several things. fuel dripping down past o-rings in the bowl while setting, low float level and evaporation to name a few.

 

[jasperjacko]

As far as vapor lock, that's only in a hot running situation usually in a system with no fuel return line to the tank. Yours should have a return line.

 

[8v-of-fury]

Hard to tell what it is doing, as it seems to be entirely intermittent! lol. I drive this car for 8 solid days of every month, and the other 3 weeks it sits at my grandmothers house while I am away working.

I can drive it back down to her place (2 hours from me) and park it there, and it will sit for 2 weeks and maybe she will start it.. maybe not.. sometimes it sits the whole 3 weeks until I come back to fire it up and drive it the 2 hours home. It will fire up indefinitely at her place even though I parked it with the engine as hot as it could ever be.. Yet it sits over night here and the carb is empty. I know it is an empty bowl situation because it will catch and run and slowly die out as though it had run out of fuel, some cranking and you get a repeated effect and then it will finally catch and run fine.

This fuel system does not utilize a return system, neither did the stock setup with the 2 bbl enrichment carb. I do get some pretty shitty running when hot too.. with a bad stumble to the idle especially in gear, it usually brings the idle down enough to bring the oil pressure light on too.

 

[jasperjacko]

That is odd. All these cars should have a return line from the factory.

 

[8v-of-fury]

I suppose.. it returns from the filter? Not from the hot part of the line or carb though.

 

[jasperjacko]

Correct

 

[kkritsilas]

Leaky fuel pump? Is the fuel filter clean or changed recently? What type of fuel (I.e. Real gas or with ethanol)? If ethanol, your floats may have absorbed some gas and float levels may be low. Just ideas.

Kostas

 

[8v-of-fury]

A leaky fuel pump would do what wile sitting? Drain back to the tank and allow the bowls to go dry?

It's 87 octane. With up to %10 ethanol. Very possible it has dropped the floats.

Just off idle seems to run better even while hot, and the power seems as good as it can be for what it is.