Flavia 2000 Coupe Hard Starting Cure

[Brian Long]

My coupe has always been tricky to start.
Problem turned out to be that the butterfly in the primary throat was not opening enough when the choke lever was fully engaged.
Cured by sweating a small piece of copper, about 0.5mm thick cut from a washer, where the actuating cam rubs on the throttle butterfly actuating link, the one with the idle speed screw.
Mixture for starting is drawn from the main jet because the strangler flap is closed by the choke linkage. If the throttle butterfly isn't opened a little bit, no fuel gets to the engine.
The strangler flap should partially open when the manifold pressure drops once the engine fires. Check the little diaphragm actuator if it doesn't do this.
Brian

[brian]

Is this just from cold or could it be related to difficulties with restarting when hot on 1800 Flavias with Solex carbs (mine at least!)?
Brian

[Brian Long]

No, it was only from cold. Once started and warming up, it was quite happy.
Starting when hot has never been a problem.
The Flavia 2000 has a recirculating fuel return to the tank. I have also fitted an electric pump which comes on if I move the choke knob from its rest position. I think if I were to have hot starting vapourisation problems in either the mechanical pump or the carburettor, the circulation of cooler petrol through the system would probably help.
Brian

[bobhenry999]

My 815 Coupe is sometimes hard to start when it is really hot, last time was when I went to Omicron a few ago to have the rear brake slave cylinders changed. I arrived in sweltering heat turned it off, and then 10 minutes later it wouldn`t start in order to get it in the workshop so we had to push it in.

A few hours later once the work was done it fired up first turn of the key.

Mine is a variante 1005 car with the Nardi conversion so it has a single twin choke Weber, but I don`t know if that makes any difference.

Bob

[Brian Long]

I wonder whether a vapour lock had occurred in the petrol pump? It is nestled down by the RH cylinder head and near the radiator. Maybe that is why the later 820 series had a recirculating fuel flow back to the petrol tank.
I seem to recall reading that Omicron had a modification that effectively provided recirculation of the fuel for the models that didn't have it.
In the hottest of Summer days here in Melbourne I have never had any problems starting a hot engine on my 820 Flavia coupe.
I have also heard of Aurelia owners pouring water over the petrol pump in an effort to cool them down. I have fitted a FACET pump, for priming the carburettor, near the fuel tank on my Aurelia. Very occasionally it might hesitate when caught in traffic on a hot day. Turning on the pump cures the problem because it pushes cooler petrol into the mechanical pump and carburettor whilst the vapourised fuel is expelled from the carburettor.
Hope this helps.
Regards.

[lancialulu]

It is a mystery. My Flavia Vignale Iniezione (kugelfisher mech injection) can also suffer from vaporisation but only if I stop the engine when very hot. It has by design a fuel return and even running the electric pump (it obviously has no mech pump) to push through cooler fuel makes no difference as somewhere in the pump the vapour is trapped. A wait of somewhere between 10-15 minutes, then it starts normally... My B12 on the other hand has not let me down at all. I have fitted a Facet to prime but have never used it otherwise. Fulvias dont seem to have this problem at all. Probably due to the fact that the carbs (although in the hot air from the radiator) are in open air and not sitting on a lump of hot metal.

[peterbaker]

Always worth checking if the car has two fuel filters. One exposed under the bonnet, the other sneakily hidden down by the tank. The one at the rear of my car had never been changed with obvious consequences.

[GG]

Have no experience with the 2000 fuel problems, but have experienced fuel issues on Aurelias. On a B24, we installed an improved performance engine (more power) with Nardi kit. The spacers on the B24 Nardi kit below the carbs are a bit thiner, and the carbs get much much hotter, especially in summer heat. And left alone (turned off after a run) they will boil out the fuel. We ran a small fuel return - not perfect, just in the feed line to the carbs - and it made all the difference. Noticed that c. 1968-1970, a number of the Italian cars added this to their carb setups. I think it comes in with s.2 Fulvias and Ferrari Daytonas, likely for the same reasons.

And our fuels are much more susceptible to this now than they were (different mixtures).

Vaporization can happen anywhere the heat builds up - in the fuel pump, the lines to the carbs, or the carb float bowls. The best answer here has been return lines and elec pump (at the back by the tank, out of the heat) in series with mech'l, run with a switch as a helper when needed.

On s.2 B20, don't have this problem with the carbs, but they are stock install. They still get very hot tho. No return line installed (don't seem to need this yet), but do use the elec pump if it gets super hot, especially on takeoff. More recently, found bad hot running was the coil misbehaving in the heat - the spark was there but much weaker. Changed that and life got much better.