• Hi Guest!
    If you appreciate British Car Forum and our 25 years of supporting British car enthusiasts with technical and anicdotal information, collected from our thousands of great members, please support us with a low-cost subscription. You can become a supporting member for less than the dues of most car clubs.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

starting ether and cold weather starting

Share this page

My shop bathroom is too well vented (outside). So I'll have to stick to the question of 'pumping the choke to enhance start-up'. I don't think it does much. But, pulling out a full choke and holding it there with the ignition switch on but not trying to start the engine probably does have some effect on start-up. If you would take the air cleaners off your SU carbs (admittedly a bit of a pain on big healeys) turn the ignition switch on, pull the choke out full, and hold it there, but don't try to start the engine, you will notice that the good old electric fuel pump is pushing the fuel right passed the jets and into the manifold. It will push so much fuel that it will often times run right out the throats of the carbs. This will certainly enhance richness to help with cold weather start-up,,,,until it floods the engine completely. But, I don't know that I would do this for a prolonged period because it might put so much fuel into the intake manifold that it may be able to cause hydrolic lock in the cylinders, maybe breaking a piston. /ubbthreads/images/graemlins/wink.gif
 
Motorhead; he said it took 2 weeks for the hair to start growing back on his legs, told me he felt like a Saturn 5 rocket sitting on the toilet when the starting fluid went off.
 
[ QUOTE ]
But, pulling out a full choke and holding it there with the ignition switch on but not trying to start the engine probably does have some effect on start-up. If you would take the air cleaners off your SU carbs (admittedly a bit of a pain on big healeys) turn the ignition switch on, pull the choke out full, and hold it there, but don't try to start the engine, you will notice that the good old electric fuel pump is pushing the fuel right passed the jets and into the manifold. It will push so much fuel that it will often times run right out the throats of the carbs. This will certainly enhance richness to help with cold weather start-up,,,,until it floods the engine completely. But, I don't know that I would do this for a prolonged period because it might put so much fuel into the intake manifold that it may be able to cause hydrolic lock in the cylinders, maybe breaking a piston. /ubbthreads/images/graemlins/wink.gif

[/ QUOTE ]

...mmm...something wrong there! The float valve should be able to totally stop the fuel if it is set up right and in good condition. The level of fuel in the float chamber should be marginally below the level of the jet so you get no flow unless sucked by manifold depression.

I suspect that you possibly have an aftermarket fuel pump that's too high pressure, or you have a faulty float valve, or your float is set to the wrong height.

AWEM
 
Hi Andrew,
I certainly agree with you. Pulling the choke lowers the jet so that a smaller diameter of the needle is in the jet which richens the mixture. Lowering the jet does not decrease the distance between fuel level (set by the floats) & the top of the jet bridge (fixed by the carb construction). I also agree with your diagnosis.
D
 
Andrew & Dave, I could agree with both of your interpretations, but I have had this condition occur on at least one car that I have worked on in recent years. It was a '74 Midget. An the carbs were adjusted alittle rich. With the choke full-on, and the key on you could see the fuel just puddling abit in the jet orifices. I have to admit that I never let the ignition switch on long enough to see if it would actually flood the engine. But it did run out of the carb throats once. I believe the Midget intake has the carbs on alittle bit more of a horizontal plane than the Big Healey. I'm not certin about the angle of the carbs, but I do remember the fuel puddling.
 
Well Guys, I was gonna stay out of grown folks conversations but I ain't never heard of carbs being flooded when the choke is pulled out and the fuel pump is energised. I do this as my initial systems all go check waiting for the fuel pump to stop clicking. I think that fella havin them type problems better go get a good set of grose jets an put em in.---Keoke- /ubbthreads/images/graemlins/yesnod.gif /ubbthreads/images/graemlins/grin.gif
 
Nope TH, You loose. No event can have more than one success in one try---Keoke /ubbthreads/images/graemlins/laugh.gif
 
Thats OK TH. It is a probability Insomnia generator.---Keoke- /ubbthreads/images/graemlins/grin.gif --------------TH! You got Mail- /ubbthreads/images/graemlins/yesnod.gif
 
[ QUOTE ]
Andrew & Dave, I could agree with both of your interpretations, but I have had this condition occur on at least one car that I have worked on in recent years. It was a '74 Midget. An the carbs were adjusted alittle rich. With the choke full-on, and the key on you could see the fuel just puddling abit in the jet orifices. I have to admit that I never let the ignition switch on long enough to see if it would actually flood the engine. But it did run out of the carb throats once. I believe the Midget intake has the carbs on alittle bit more of a horizontal plane than the Big Healey. I'm not certin about the angle of the carbs, but I do remember the fuel puddling.

[/ QUOTE ]

I don't dispute that you've had the symptoms - what I'm saying is that it is not how things should be !

If fuel is flowing through the jet of an SU carb when the engine isn't running then there is a fault or it's not been set up right. Only exception is if you are parked on a 1 in 4 slope with the float chamber on the upper side of the slope. /ubbthreads/images/graemlins/lol.gif

AWEM
 
Andrew, you are /ubbthreads/images/graemlins/lol.gif But you are correct, if you have a stuck needle valve or the excessive Carb inclination and high ambient temperature which forces the fuel past the needle valve rather than overflowing out of the fuel filler cap and down the back of the car.---Keoke
 
Ah Andrew, now we might really be getting to something here. Let's see, a 1 in 4 slope (so that you can make a quick get-a-way) And a float adjustment set alittle too high. I think you're right, something was set up alittle out of adjustment. but it never caused any problems because I never let the switch on for very long without starting the engine.
 
[ QUOTE ]
Ah Andrew, now we might really be getting to something here. Let's see, a 1 in 4 slope (so that you can make a quick get-a-way) And a float adjustment set alittle too high. I think you're right, something was set up alittle out of adjustment. but it never caused any problems because I never let the switch on for very long without starting the engine.

[/ QUOTE ]

Bank job by any chance? Probably better to use a less distictive gettaway car in future. Where did you stash the loot? /ubbthreads/images/graemlins/lol.gif /ubbthreads/images/graemlins/lol.gif /ubbthreads/images/graemlins/lol.gif

AWEM
 
Back
Top