Stalling after start when hot on hot days .. vapour lock?

[Route--66--]

Hi all

'65 200ci with autolite 1100;
Stalls after driving 10 -20 yards when the engine is hot if it's a hot day.

After driving and up to temperature on a hot day I'll turn the engine off, maybe leave it for a minute or 10 ... it'll start fine and pull off but after a few yards dies completely .. normal run of things it'll restart after 3 or 4 ish seconds of cranking and pull off .. then sometimes stall a second time.. after the second stall it's always fine!

Could this be vapour lock or something else? .. I've sheathed my fuel pipe from the front of the engine right up to the carb in fairly thick rubber gas/petrol type pipe to no advantage .. any ideas?

Cheers!
D

 

[bubba22349]

The fuel maybe leaking out or evaporating out of the fuel bowl when it sits.

 

[Route--66--]

.hhmmm// I did have to take the top off the carb last year .. can't remember if it was before or after this trouble started . . maybe it needs a better seal.. would it evaporate that quickly though? ..

 

[bubba22349]

Evaporation would take sitting quite awhile, but if there is a leak due to porosity in the bottom of fuel bowl casting it can happen fairly quick.

 

[mluck]

thats happened to me a few times this month...(102 heat index in mn)...i had a 57 chevy in the 70s that this happen to all summer....my dad drill a small hole in the gas cap ...never said why..are the early mustangs gas tank vented....

 

[JackFish]

A failing or marginal coil will be effected by heat soak.
Just throwing something else out there.
After shutting down the heat soak from the engine really effects the gas in the line going to the carb.
On mine it started forcing it out at the fuel filter to the point where gas drips all over the hot manifold. Very scary.
My plan is to run a return line back to the tank.

 

[Route--66--]

interesting comments thanks.
Not sure if the tank is vented .. may be worth a check .. although saying that.. I would have thought a hot day would pressurise the tank and line rather than create a vacuum . ..?

Coil .. hmm .. something I hadn't thought of actually .. .. although wouldn't have thought that it would have 'cooled' enough after a few seconds to then be fine .. hmm interesting lateral thought though . .

Pretty sure I haven't got a leak in fuel bowl wut will have a look next time before I re-start to see if I can see anything .. perhaps I might try some MASSIVE insulation around the fuel pipe - go totally overboard just to see if it makes any difference ..

hmmm......

 

[Varilux]

If heat is causing the evaporation, perhaps a spacer/insulator for the carb would help?

I had a problem with stalling when hot on my 1100 (actually, a knock off that was like an 1100) a couple years ago. You might also try bypassing the heater line around the carb as well (if your carb is like mine, it has a heater hose that runs through the base of the carb).

In my case, it ended up being a broken automatic choke that was managing to flop closed when hot (didn't notice because it doesn't get cold that often here in Texas- and I don't drive it when its cold anyway).

If its happening when you are pulling away, it could perhaps also be a weak accelerator pump shot (combined with an already low amount of fuel in the bowl)?

 

[FalconSedanDelivery]

Heat Soak , Fuel Percolation , they always were borderline on doing it , then they added Ethanol , the best cure ( although time consuming) , is to add a return line to the fuel system and a Fuel Pressure regulator set at 4.5 psi Max , a inline fuel filter is readily available that makes the plumbing easier , add the line ( min 1/4 ) and run it back to the filler neck , it will keep the gas as cool as possible , a insulator under the carb helps as does getting the engine to run as close to 160-180, ( not easy in a hot climate in am early Mustang with a stock cooling system as the grill opening is small compared to a Falcon )

 

[rbohm]

Heat Soak , Fuel Percolation , they always were borderline on doing it , then they added Ethanol , the best cure ( although time consuming) , is to add a return line to the fuel system and a Fuel Pressure regulator set at 4.5 psi Max , a inline fuel filter is readily available that makes the plumbing easier , add the line ( min 1/4 ) and run it back to the filler neck , it will keep the gas as cool as possible , a insulator under the carb helps as does getting the engine to run as close to 160-180, ( not easy in a hot climate in am early Mustang with a stock cooling system as the grill opening is small compared to a Falcon )

in addition and electric fuel pump can also help in hot weather as it ensures a constant supply of fuel.

 

[chopperman69]

A failing or marginal coil will be effected by heat soak.

I had a bad plug wire from the coil to the cap act similar to this. Sure is a cheap thing to check.

Scot in OKC

 

[Route--66--]

Cheers guys will check .. hmm.. thinking about it .. did change the pump before it started acting up .. .. . .
Will check coil wires too cheers
I'll leave the feedback line thanks as it's not thaaaat much of a problem to warrant that extra work..

I know this is an odd one but has anyone installed an electric and mech pump ... . to mainly run off mech but electric there for times like when car hasn't been used - to prime the float chamber before starting... and hot days of course... !

OOO Loving that econoline !

 

[rbohm]

8) most people that use a mechanical and electric pump at the same time usually put the electric pump inline back near the tank so it feeds the mechanical pump. this gives constant pressure to the mechanical pump. one nice thing about this arraignment is that if the mechanical pump fails, the electric pump still feeds the engine.

 

[Route--66--]

cool, thanks rbhom, that's the setup I was thinking of.. if the electric pump was only used occasionally would the mech pump happily pull the fuel through ok?
Cheers!

 

[rbohm]

cool, thanks rbhom, that's the setup I was thinking of.. if the electric pump was only used occasionally would the mech pump happily pull the fuel through ok?
Cheers!

that depends on the electric pump. some are just electric versions of the mechanical pump, others use a vane and rotor system to pump fuel. personally i would use it all the time, just wire it up to run when the ignition is on.