CIS to Carb - Now Cold Starting Probs

[madpcar]

I have just changed from CIS to PMOs and am having Problems with cold starting. The car will turn over for a few of minutes and then coff and start. Once warm it runs fine.

Do I have to change the timing and/or spark plug gap ? Plugs are at 0.070mm as per CIS. New plugs/leads/rotor and cap. I have a Crane XR700 with coil.

Help ?????.

thanks

Dan

[RWebb]

on a 911, carbs have no automatic or even manual choke - they didn't tell you that before doing the swap??

you have to be the choke...

[JP911]

As Randy said, no cold start feature built into 911 carbs.

Here's the procedure for starting the car cold:
1. Turn the key to power the fuel pump.
2. Depress the gas pedal to the floor 3-4 times.
3. Turn the key (it should fire)
4. Feather the gas pedal until the engine is running smoothly
5. Either hold the gas pedal with your foot or hand throttle (if your car has one) until the engine idles normally.

[madpcar]

I did the swap myself - so I'm learning as I go. I will try Jon's method and see how I go.

Do I have to change spark plug gap/timing as well ?

Since the conversion, my hand throttle does not seem to do a thing ??? Any ideas

Its a 74 S 2.7.

[RichF]

My webers dot he samething, it just something you have to deal with, as for the hand control, it may have came off the throttle rod.

[RWebb]

if the car has been sitting a few days, then add this to JOn's procedure:

1.5 - wait half a minute for the pump to fill the float bowls on the carbs (the fuel evaporates over time)

[RWebb]

PS - leave everything else alone for now.

You will have to change the cams & pistons to get much add'l. power, but the motor will be a lot more fun with just carbs.

[Joe Bob]

Two, three good pumps after the fuel pump changes tone, 1/4 throttle, crank it.....

[madpcar]

Just want to say thanks to all who helped - followed the methods above and it starts way better !

[al lkosmal]

My neighbors love this routine at 6:30 in the morning, when i'm leaving for work. My sport muffler is loud enough, but occasionally I get the start up procedure wrong and spark off a bunch of unburnt fuel, resulting in a backfire like a rifle shot. The sound really rolls across the valley. Good morning Mount Vernon!!!!

[JV911SYDNEY]

Originally Posted by al lkosmal

My neighbors love this routine at 6:30 in the morning, when i'm leaving for work. My sport muffler is loud enough, but occasionally I get the start up procedure wrong and spark off a bunch of unburnt fuel, resulting in a backfire like a rifle shot. The sound really rolls across the valley. Good morning Mount Vernon!!!!

god i cant wait until i do my PMO conversion...its going to be freakin sweet

[cfries]

I do the same procedure on my Webers and it works fine. Going to PMO's very soon, but I'm expecting the procedure to be the same. Woke up my neighbors this morning at 7:00am with a sport muffler as well ! gotta love it.

[Formerly Steve Wilkinson]

My PMOs start just fine if I pump them three or four times--more if seriously cold--and it'll catch on the second try, though my daughter can usually start it on the first cycle...

[RoninLB]

Originally Posted by madpcar

I did the swap myself - so I'm learning as I go. I

Do I have to change spark plug gap/timing as well ?

Its a 74 S 2.7.

make take a little time to feel out after you crank it if you gave it too much fuel or not enough. Listen to how it fires. Develop a feel for the gas pedal when cold starting.

I'm not positive on your distributor but disconnect any vacuum retard and set max timing at 35 degrees. Leave vacuum line plugged and run without it.

[butzi73]

It took me a while to get used to this procedure as well, but now I actually enjoy it. I do 2 pumps then it's just a matter of getting a feel for feathering in the gas as you are cranking.

When I was first learning this I would not give it enough gas and it wouldn't fire, or more often, I would give it too much and the engine would rev too hard for being cold and therefore the cold oil pressure would spike too high. Once you get the feel for feathering in the gas watch the tach as see if you can keep the revs between 1k and 2k during start up. I like to watch the oil pressure gauge and make sure I keep it below half way during those cold starts.

[javadog]

You can use small jabs of the throttle to squirt more fuel in, via the accelerator pumps, if it tries to die. Just little jabs, not enough to raise the revs much at all. It takes practice.

JR

[RWebb]

the above is what we all used to do back in the olden times before new-fangled things like automatermerical chokers began appearing on our carbs.

[moneymanager]

If your hand throttle isn't working, take the time to fix it. My PMO's like 6-8 gas-pedal-to-floor strokes with the hand throttle full up. Car lights in a millisecond and I instantly push the hand throttle down about 1/2 way. Then I let it stumble and cough for about 20 seconds without touching the gas pedal. If you try to give it gas at this point it will likely stall. After 20 seconds or so it begins to sound almost smooth. In another 10 seconds the revs increase some more and it is running as it should.

[jmcn3rd]

When I first turn the key, after a couple of seconds, you can actually hear a bubbling like noise from the fuel pump/carbs which I have taken as the carbs being ready to go. I also noticed that a very slight turn of the air screws makes a gigantic difference in starting. Too much, too rich and stinks up the house. Too little, very hard to cold start and coughing noise. As others mentioned, there is a technique that you will master and it will be very gratifying once you get it. I also noticed if you pump too many or are too strong on the gas, my car will shoot black soot out of the pipe. Just the right amt. of pedal pumps and feathering get it done right. Enjoy.

[ael911]

+1 on what Moneymanager said, I love having the hand throttle with my PMOs. I drive my car once a week so the bowls are usually dry or very low when I go to start. Three full pumps on the pedal and it fires on the first turn of the key. I have to be delicate with the hand throttle setting as I can easily send the motor over 4k rpms with hand thorttle fully engaged. I set the hand throttle to idle at about 2k rpms for a few minutes and its good to go. The hand throttle also doubles as a cruise control for those long high way stretches...