Hi My 79 308GTB has suddenly developed some starting problems as follows, First start of day---- no problem, go for run and it will restart easily within a couple of minutes, leave it for an hour or so and it will need cranking for at least 30 seconds before spluttering into life. Next day it will start easily again !? I can hear the pump running o.k. I have checked out all the other posts on the forum but they all seem to related to Injection models, is my problem normal, is it the fuel evaporating in the carbs when left for a while, because of the heat from the engine? Regards Phil
sounds like vapor lock, my 308 carby did it until i converted over to TWM injection. i have a thread out there on insulating the valley under the carbs - it REALLY helped keep the heat off the fuel bowls.
What are you doing with the throttle when trying to restart hot??? Mine starts easily within 2-3 seconds of cranking verrrry hot with the throttle cracked about 1/2" at the pedal. Any pumping or other techniques just don't seem to work. Just ease it open a little and let it crank--works for me...even in 110 degree heat here in AZ.
next time I go out on a run I will try that method, I seem to to think that I press fully down on the pedal, never really taken much notice, but I will give it a go and let you know.
Just returned from a 15 min run,everything running o.k. although when ticking over it pops a little bit. Gave it 30 minutes and tried to start it,I tried with just a little throttle, no luck. I then tried mAshing it and it finally started after about 30 seconds churning. I stopped it and started it again straight away with no problems at all, this is weird !!!
not so weird, fuel is boiling in the bowls - on webers , the bowls hang out there getting intense heat from the engine - just like a holley carb on a vette V8 - thats why they make an insulator plate for the holley - very hard to do with 4 webers and linkage - thats why i went with fabric like insulation under everything... not only did i unsulate the valley under the carbs, but i also insulated the fuel line running around the carbs. sure helped, but did not get rid of it entirely. another way is to duct fresh air onto the carbs under the airbox - i ahve heard thi works wonders too and was going to be my next step, but now i dont have to due to FI..........
i agree. i think there is a fuel flow problem somewhere. i have never had an issue like that warm. ( 4 carb ferrari's) + i start all of my old carb cars the same as the above method, with no issues. i would drive the car from home on a nice run, and return home. hook up a pressure gauge and then turn the key to start it hot. the pump may be weak when the engine compartment is hot as the heat raises resistance in the wires. someone please remind / correct me, but i think the carb fuel pressure should be around 6.5 psi or so ? i wonder if the check valve going to the right hand fuel tank after the carbs (American left hand drive car) could be bad?
ps : make sure that one of your carbs is not leaking fuel after shut down and flooding the carb making it hard to start. if it does this and sits awhile until its cold, it will still start cold when you open the throttles all the way as you would for a cold start. i had one 308 that had one carb with a sticky float that would weep fuel into the bowl after being run.
