Yes, they do....ask me how I know......

My 914-6 does not warm start well. Webers boil over. Cold start is great.

My 70 911 was just the opposite. Easy start once warm.

Does your six have the insulator blocks under the intake manifolds? I have a 1983 911SC with 46mm PMO carburetors in the Florida heat and zero problems starting hot. Also the rest of the car has to be up to snuff....ignition,distributor,fuel pump,plugs and wires ect.

No, but I'm going to add them (under the carbs) after carb rebuild.

But as I said, my 2.5 911S with Zeniths started great hot. I think it's a Weber thing, and the PMO insulators are my hoped for salvation.

How many fuel pumps are running to feed those 46s?

The insulators go under the manifolds to keep the heat from transferring from the heads into the manifold which then transfers into the carb body. On my SC I am running the stock CIS fuel pump with a PMO pressure regulator. It has performed perfect for over 2 years. For my GT clone I am running 3.0 911 engine with 40mm Webers. I have the insulators installed on that setup also but car not running yet. Good luck with your hot start issue.

I know that at least one SC (stock, with CIS) will occasionally have hot start problems in very very hot conditions.

--DD

Thanks, I had it in my mind they went under the carbs.

Just checked the PMO website, not too clear on accessories, but I didn't look too hard yet.

My SC...when it had a 3.0 and CIS had hot start issues, it was the 14 dollar check valve.

My current SC has a 3.6 and it's the stoopid solenoid just like my 914/6....

PMO makes a drill fixture that you place in the carbs and drill "vent" holes to help stop perculation in the float bowls. It seems to help.

my 3.0 w cis has a hot start problem..would love to get that figured out

Check valve in the neck of the fuel pump....