Thans for your feedback
My fuel fiter have 6k kms, but I will try change it for a new one with better quality. The carb had a revision at the same time.
I notice the carb flows a little fuel when this problem occurs.
- Thread starter benchseat
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My fuel fiter have 6k kms, but I will try change it for a new one with better quality. The carb had a revision at the same time.
I notice the carb flows a little fuel when this problem occurs.
Britsh camp, Malvern?
jjad
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Not a million miles away, but further south. (In fact, I'm struggling to remember what it's called now!)
malcolm
& Clementine the Cat
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Just another thought on hot starting. I've had troubles on other cars with the exhaust manifold to getting too hot.
What advance you can run is influenced by fueling. There is an ideal air fuel mixture where things work nicely. Go leaner than that and the burn becomes slower. You can compensate for this by advancing the ignition but that causes higher temperatures and tends to burn valves., Sticking at the factory ignition settings will mean the combustion is still going on when the exhaust valve opens so the exhaust manifold gets hot. Of course we've also got 40 year old distributors where the advance springs don't work too well.
The R4 was always a bit lean but modern fuels increasingly make them even more lean and can cause issues. They've bunged 10% of stuff in that doesn't work so well and the general approach is to increase fueling by 5%. Annoyingly there is no adjustment in a fixed jet carb other than changing the jet. But the jet can be changed by drilling it out to a slightly larger hole size.
What advance you can run is influenced by fueling. There is an ideal air fuel mixture where things work nicely. Go leaner than that and the burn becomes slower. You can compensate for this by advancing the ignition but that causes higher temperatures and tends to burn valves., Sticking at the factory ignition settings will mean the combustion is still going on when the exhaust valve opens so the exhaust manifold gets hot. Of course we've also got 40 year old distributors where the advance springs don't work too well.
The R4 was always a bit lean but modern fuels increasingly make them even more lean and can cause issues. They've bunged 10% of stuff in that doesn't work so well and the general approach is to increase fueling by 5%. Annoyingly there is no adjustment in a fixed jet carb other than changing the jet. But the jet can be changed by drilling it out to a slightly larger hole size.
Jnr-Renospeed
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My carb has a larger main jet drilled out to 1mm - and I have had no issues with hot starting and it is a general performance gain to do so as Malcom says.
It is good to make sure the carb to manifold spacer is in place and in good condition as well as the air intake is in the hot weather position.
With hot starting I always turn the key with my foot pressed on the accelerator, sometimes all the way down if the car has been sitting and heatsoaking for ~10 mins. The car will crank and fire and kick out a bit of soot, then hold your foot gently on the accelerator to draw fuel into the carb..
..modern petrols evaporate at lower temps than old stuff and bubble into the cylinders flooding them whilst leaving the carbuerretor dry when the engine is turned off whilst hot and this is often the cause of starting problems.
It is good to make sure the carb to manifold spacer is in place and in good condition as well as the air intake is in the hot weather position.
With hot starting I always turn the key with my foot pressed on the accelerator, sometimes all the way down if the car has been sitting and heatsoaking for ~10 mins. The car will crank and fire and kick out a bit of soot, then hold your foot gently on the accelerator to draw fuel into the carb..
..modern petrols evaporate at lower temps than old stuff and bubble into the cylinders flooding them whilst leaving the carbuerretor dry when the engine is turned off whilst hot and this is often the cause of starting problems.
Last edited:
AdamWilkes
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I tried the petrol by-pass circuit to return warm petrol to the tank to no effect in the carb really; then I just fitted a pulsing electric fuel pump which only worked when the ignition was on but the engine not running (driven via a small relay using the ignition warning light I think). Didn't solve the issue but made it easier to fill up the carb bowl - just leave the ignition on for a few seconds before cranking 
jjad
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And before I do forget, I'll write it here: it's Crickley Hill Country Park in Gloucestershire