Engine starts easy when cold, But acts like its flooded when warm

hello group -
I've only owned my car for two months, so I'm not sure "whats normal."

The car is a 2009 Vintage, with a 1915cc motor. Twin Solex - -don't know what size.

Starting it when its cold, fires right up ! But trying to start it
5 minutes after driving it, it cranks alot before firing. Would this be just an carb adjustment? Anyone else have these symptoms?

Thanks in advance
Simi Mike

sounds like running out of gas, try looking at the fuel filter when this happens, see if it is empty. bill

Mike - try pushing the gas pedal (1 time) to the floor and release, then crank engine! See if that works.

Vapour lock?

VAPOR LOCK
A condition caused when fuel fails to flow to the engine because of high fuel vapor pressure in the inlet fuel line or internal fuel pump cavities, caused by high heat or heat build-up.

My old Porsche 912 used to do this all the time. Heat transferred from the engine via the manifolds into the carbs would vapourize the gas left in there and create a vapour lock, even with the thick insulators between the carbs and the manifolds installed. I fixed this somewhat by switching to an electric fuel pump, don't know if the pressure from that pump overcame the vapour lock or what but it improved the hot starts considerably.

Mike, I don't pretend to know a lot about those carbs, but your problem mirrors mine. I can crank it for ever if it's hot and if I pump the gas it floods for sure. If I hold the pedal to the floor and don't pump it the butterflies open wide and let in more air and it fires within a few spins. This method used to work for old bikes when you dumped them and they flooded hopelessly and it works for my old carbs. Your carbs are new so I suspect there is an adjustment They're all different. Whatever works...good luck

Mine sometime does this. Pretty sure it's vapor locking even with the pump up front. I treat it like it's flooded and hold the pedal to the floor whilst cranking. Starts right up.

~WB

Thanks Guys -
I'm going to take the car out tomorrow for a spin. We had alittle rain last night, and the streets are still wet.

I'll try your suggestions. It makes alot of sense to hold down
the pedal (to open up the butterfly) and let the carbs get more air.

Will give you an update tomorrow.

Thanks all - - for replying

Simi Mike

Mike why don't u go ON the cruise with us this coming sat morning.
we are taking route 2 off the 210

It seems that my engine likes to flood when it's warm. So try what I ALWAYS do when starting a hot or warm engine - treat it like a modern fuel injection engine! That is:

DO NOT touch the gas pedal.
Turn the engine over using the key.
After a 3 or 4 seconds it will start to sputter, and "feel" different.
IMMEDIATELY give it a gentle push on the gas pedal.
BRAPP, and we're off!

Perhaps yours would react the same?

The likely culprit is too much fuel pressure or floats set too high. If the float level is to high and or the fuel pump residual pressure to high then the carbs will bleed off the extra and actually flood you out. This will dissipate after say an hour or so but will be a bigger problem if you shut down, go in for a cool drink or fill up the tank and try to hit the road again. The best solution to start the car now is to SLOWLY push the throttle to the floor (do not pump) and crank until the motor fires. By opening the throttle all the way you put more air in the chambers (not enough is moving to draw much fuel in) and lean out the flooded condition.

Give it a try but check those float levels and fuel pump pressure. More than 3lbs of pressure at the carbs is too much.

Good sound suggestions above. I would also add to see if you have insulators under the carbs (between the carb and the intake). If they are available for your engine/intake/carb configuration, I would suggest you use them. As soon as you shut your engine off, the air traveling through the carb/intake to the engine STOPS. So everything heat soaks which boils the fuel in the carb(s). The insulators will reduce fuel boiling in the carb and greatly improve hot starts.

angela

My Vintage did the exact same thing and I think Dave has it right. The engine was flooded and needed more air. I finally had Kirk replace the crappy carbs it came with (don't even know what they were) with some Webers and the problem is now gone.
Troy

my Spyder's CB Performance 2165 engine did the same thing (cold start ok - hot start 'iffy' or not) - I had a high torque starter put in and had no problems thereafter.
.
RickJ

Mike; I put dual Empi Kadrons on my 2020cc, had the same problem. I would shut the engine off after driving for a while. Fuel pump (mechanical) built so much presure you could see it entering the carb throats. Cured problem with a .5mm bleeder that sends excessive presure back to tank when the engine not running. Has no effect on performance.

put electric fuel pump in with a regulator and seperate switch, then you cane turn the pump off before shutting down, will probley prevent a;; you problems. bill

Everett, buy a big stack of gaskets and shim your fuel pump! Buy or borrow a fuel pressure gauge, set it at under 2 psi, 1.5 is perfect. You'd be amazed how much better it'll run, I once put 7 gaskets under one to drop the pressure.

Ditto what Danny said ....1.5 lb.

Thanx Doc, I'm going to try that when I get back to Michigan in April. This pump delivers way more fuel than needed.