Hot start query.

Mad4slalom

Mad4slalom

Well-known user
Hi all , anyone have any advice for a hot start procedure?
if I switch off and restart within say 5mins or so then she fires up instantly. But if she has sat for 30mins plus then she turns over rapidly as if no fuel in there to compress. So I have to pump the throttle a few times to then get her to fire. .
today she hsd stood for 40mins , I presumed she would need a few pumps to get some fuel through, I gave a couple but still not enough so then it took two or three more goes before she fired up. Fine again while hot , fine when cooled right down but its that period of time say 30mins is the problem. What do you guys do? 650 double pumper and no choke. 👍
 
Roscobbc

Roscobbc

Moderator
You could be suffering from mild percolation - the fuel in the carb and fuel line is boiling-off fuel when stationary. Heat rises - with a V8 engine that heat (remembering that the engine is not being cooled by the radiator) will rise through the block - through the heads - up through the inlet manifold in to the carb......and will vapourise the fuel in the float bowls. Obviously worse on hot and humid days. There are way to try and minimise it - like a 'stack' of mixed ally/phenolic spacers and carn gaskets - routing fuel lines away from heat sources - wrapping fuel lines with heat reflecting ally foil - taking things further - if you have headers, replacing with ceramic coated units. Flushing cylinder block (if running hot)rad? uprated
 
Mad4slalom

Mad4slalom

Well-known user
Roscobbc said:
You could be suffering from mild percolation - the fuel in the carb and fuel line is boiling-off fuel when stationary. Heat rises - with a V8 engine that heat (remembering that the engine is not being cooled by the radiator) will rise through the block - through the heads - up through the inlet manifold in to the carb......and will vapourise the fuel in the float bowls. Obviously worse on hot and humid days. There are way to try and minimise it - like a 'stack' of mixed ally/phenolic spacers and carn gaskets - routing fuel lines away from heat sources - wrapping fuel lines with heat reflecting ally foil - taking things further - if you have headers, replacing with ceramic coated units. Flushing cylinder block (if running hot)rad? uprated
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Thanks rossco, the car runs very cool with no ticking when hot like some engines. All new rad and water pump, pipes etc. No headers, just rams horns. So could look at carb spacing and fuel pipes 👍
 
Mad4slalom

Mad4slalom

Well-known user
Derek Nicol said:
I still havent found Ethanol free up here in the civilised world either.

(love Cornwall really)
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Thats the trouble with Cornwall in summer, all the civilised folk from up there , come down here and make it uncivilised 😩😂😂👍 this year is going to be extra carnage with the next stage of dualling the A30 in progress, along with folk doing staycations instead of flying off for their hols . Maybe Chuffer can organise a “Cornish riviera”
Steam train to ease the pressure on the roads.
 
Chuffer

Chuffer

CCCUK Member
Derek Nicol said:
I still havent found Ethanol free up here in the civilised world either.

(love Cornwall really)
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It should be Ethanol free Esso up in this part of the world . My understanding is the E5 label on the pump is some sort of requirement . Probably to appease the damned EU !
 
Derek Nicol

Derek Nicol

Well-known user
Chuffer said:
It should be Ethanol free Esso up in this part of the world . My understanding is the E5 label on the pump is some sort of requirement . Probably to appease the damned EU !
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I wouldnt trust that, apparently some Esso do, some Esso dont.
 
Derek Nicol

Derek Nicol

Well-known user
Although our pumps have E5 labels on them, our Synergy Supreme+ 99 is actually ethanol free (except, due to technical supply reasons, in Devon, Cornwall, North Wales, North England and Scotland). Legislation requires us to place these E5 labels on pumps that dispense unleaded petrol with ‘up to 5% ethanol’, including those that contain no ethanol, which is why we display them on our Synergy Supreme+ 99 pumps... How Stupid is that!! :mad:

There’s currently no requirement for renewable fuel, like ethanol, to be present in super unleaded petrol although this could change in the future, in which case we would comply with any new legislation.

I went to the only Esso in town and every single pump had E5 on it so i figured they didnt have Ethanol free
 
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Chuffer

Chuffer

CCCUK Member
Wrong !!!! It might be worth noting that the Esso stations on both sides of the A45 dual carriageway near the Earls Barton junction sell it when you are next over this way .
 
Mad4slalom

Mad4slalom

Well-known user
Chuffer said:
Wrong !!!! It might be worth noting that the Esso stations on both sides of the A45 dual carriageway near the Earls Barton junction sell it when you are next over this way .
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Hmm , I will have to bring a load back to cornwall on my next oxford run.😂👍
 
Oneball

Oneball

CCCUK Member
If you’ve got a mechanical fuel pump do you have to turn it over first then pump it or does just pumping it then trying to start it work. If it’s the first one it’s probably not vaporisation as there’s fuel in the carb.
 
Mad4slalom

Mad4slalom

Well-known user
Oneball said:
If you’ve got a mechanical fuel pump do you have to turn it over first then pump it or does just pumping it then trying to start it work. If it’s the first one it’s probably not vaporisation as there’s fuel in the carb.
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If i turn it over without pumping throttle , the motor spins quickly without firing as I think there is no fuel in there to compress. It will then start after i have pumped 3/4 times. I did try pumping first before turning over the other day and whereas this works from cold it didnt help much on a warm engine. 🤔
 
Roscobbc

Roscobbc

Moderator
The starting procedure I use on mine is to turn the engine over for as long as it takes to get oil pressure (If you haven't got a gauge - or it doesn't work the clue is the cranking slowing as full cold pressure is acheived) - I don't have a choke so 3 or 4 partial 'pumps' on the DP's gas pedal gets it firing. 'Feathering' the gas pedal with light pumps keeps it running. When the engine was new and 'tight' if it had been used only a couple of days previously I didn't need to do any of that - it would fire-up instantly. Hot starts - well, there are 'hot starts' and 'hot starts'. A typical hot start could be after getting gas where its been standing for perhaps 5 minutes. So do you simply turn the key and expect it to start? - or - perhaps expecting some minor vaporisation give it a quick pump on the gas pedal? - sometimes I have to do both - if the first time it doesn't start give it a pump and try again. You'll perhaps need to get accustomed to the characteristics of your particular car. Oh, I haven't factored-in the possible effects of 'heat-soak' on the starter motor and that refusing to rotate at a worthwhile speed.......always a potential issue for BB engined cars......
 
Mad4slalom

Mad4slalom

Well-known user
Roscobbc said:
The starting procedure I use on mine is to turn the engine over for as long as it takes to get oil pressure (If you haven't got a gauge - or it doesn't work the clue is the cranking slowing as full cold pressure is acheived) - I don't have a choke so 3 or 4 partial 'pumps' on the DP's gas pedal gets it firing. 'Feathering' the gas pedal with light pumps keeps it running. When the engine was new and 'tight' if it had been used only a couple of days previously I didn't need to do any of that - it would fire-up instantly. Hot starts - well, there are 'hot starts' and 'hot starts'. A typical hot start could be after getting gas where its been standing for perhaps 5 minutes. So do you simply turn the key and expect it to start? - or - perhaps expecting some minor vaporisation give it a quick pump on the gas pedal? - sometimes I have to do both - if the first time it doesn't start give it a pump and try again. You'll perhaps need to get accustomed to the characteristics of your particular car. Oh, I haven't factored-in the possible effects of 'heat-soak' on the starter motor and that refusing to rotate at a worthwhile speed.......always a potential issue for BB engined cars......
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Thanks roscob. I am starting from cold ok , i am starting hot instantly, its the 30 min restart where the fuel seems to have evapped away is the tricky one.
 
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