Joined: Aug 2017 Posts: 919 Threads: 18
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Location: North Yorkshire
It looks as if the carb float chamber needs to be filled before you use the starter. Presumably you have a mechanical fuel pump on the crankcase? If so, use the priming lever on the fuel pump to fill the carb. You will be able to tell by the sound when the float chamber has filled. I suspect the engine will then start on full choke no problem. If you have an electric fuel pump and it clicks a lot on turning on the ignition, that is a sign that the float chamber is empty. You may have a gravity feed, in which case I would fit an electric SU pump into the system!
Joined: Aug 2017 Posts: 613 Threads: 19
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Location: Hampshire UK
Hi Venn
My experience with SU equipped cars is that they normally start very readily from cold if the float chamber is primed first. This happens automatically if you have an SU electric pump. With an AC mechanical pump you need to use the priming lever until you hear/feel the float chamber is full. If you are too lazy to open the bonnet (me), 6 or 8 turns of the starting handle achieves the same. With my own car, once the first cold start of the day has been achieved, the car will re-start with no choke if the engine is anything off cold.
With the choke knob pulled out fully, the jet assembly should be lowered a good fraction of an inch and the throttle cracked open to the fast idle setting. The top of the jet is then practically level with the fuel, so it needs very little pressure drop from cranking airflow for fuel to be drawn into the engine. I wonder if either the choke cable movement is somehow being constrained, or if there is a problem with too low a level of fuel in the float chamber ?
I'm not a fan of Easy Start, as it washes off any oil film in the cylinders.
Joined: Dec 2017 Posts: 1,160 Threads: 68
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Location: Nottinghamshire. Robin Hood County
Car type: Austin Ruby Mk1 1935
05-10-2021, 04:43 PM
(This post was last modified: 05-10-2021, 04:57 PM by John Mason.)
Venn, How often do you refill with petrol. Does it start easier when you have new petrol. I have a Ruby that starts from cold straight away if the petrol in new but is somewhat of a pig (no disrespect to swine.) when the petrol is getting old. I put it down to the ethanol evaporating off more quickly than straight petrol. New or old petrol starts straight away when warm.
John Mason.
Would you believe it "Her who must be obeyed" refers to my Ruby as the toy.
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Do you have an original distributor fitted or an electronic type such as accuspark?
Joined: Jan 2019 Posts: 1,567 Threads: 20
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Location: Bala North Wales
Car type: 1933 RP Standard Saloon
With my RP, which has a (replacement) mechanical pump and a Zenith carburetor, I have found that the float chamber tends to drain if the car is left standing for a day or so. Since I have a ritual for starting from cold which involves checking oil, water and priming the carb, my car starts usually within a couple of revolutions of the engine every time, even if the battery is a bit 'iffy'. Keeping the point and plugs in good condition tends to eliminate ignition problems.
Joined: Aug 2017 Posts: 1,193 Threads: 71
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Someone did say to me once that 80% of carburettor problems are electrical....
Joined: Dec 2017 Posts: 1,160 Threads: 68
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Location: Nottinghamshire. Robin Hood County
Car type: Austin Ruby Mk1 1935
Other than blowing out the jets I was always taught to leave the carb alone until you have checked ignition and timing.
John Mason.
Would you believe it "Her who must be obeyed" refers to my Ruby as the toy.
Joined: Aug 2017 Posts: 1,230 Threads: 33
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Location: Salop
Car type: '28 GE Cup. '28 AD Chummy '30 RL Saloon. '34 RP Saloon. Too Many toys!
Peter.
What is the oil consumption? and what do the plugs look like?
What does the compression feel like on the handle?
Do what you normally do, crank it for a bit, then takr a plug out. Is it dry or is it wet with fuel.
If its wet itll be an ignition problem.
If its dry, do a little test. Pour a thimble full of fuel down each bore, replace everything. Does it then fire?
Sounds to me like you could have compression issues and the engine has to build some by cranking before it will suck the fuel out of the carb. And without fuel, it wont go.
I've got one here with the very problem. It doesnt burn a hell of a lot of oil, but it does foul the plugs (H/C head) eventually. Keeping the plugs clean and priming the carb with the pump before a cold start save a lot of pain on the battery. I will put another block on it one day. Trouble is it goes like stink
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Hedd in my younger days, I ran my RL with clapped rings and high compression head. I was always oiling plugs. Then a friend who competed in 750 club races, told me to use long reach plugs. Cured the plugs from oiling up, but not the oil comsumption!
John
