Need Help with Startng Issues, Hot and Cold

[Irish911]

I am a new owner and have a '70T with Webers that doesn't start easily, either hot or cold and am hoping those of you more knowledgable can steer me in the right direction.

When cold I lift the throttle lever about 3/4 up and pump the accelerator 3 or 4 times. I turn the key and hear the pump running for a few seconds and then turn it all the way. The car fires up and then will immediately die if I don't tap on the accelerator. If I take my foot off the gas it then dies again. I have to keep ithe rpms running at 2-3K and constantly pump the gas for about 30 seconds to warm it up. It also tends to stutter during this warm up period. If I put it into gear and then slowly depress the gas it dies. If I tap the gas to get the rpm's up it is OK. Once the engine has run for maybe 5 minutes it is OK. Idles around 900rpm when warm and accerates great. Does not stutter when warmed up. Because the car runs well when warm/hot I don't think I have a fuel delivery issue.

When hot the car takes maybe 10 seconds before the engine starts and then it is only running at around 400rpm. It will then slowly climb back to 900. It's like it's not getting gas at first or maybe not enough. I do not touch the gas when it is hot prior to starting. I have tried lifting the throttle lever half way prior to starting hot but it doesn't seem to make a difference. Because it takes so long for the engine to catch when hot sometimes I think it won't start.

The car has new plugs (Bosch W5CC) and new wires. Coil is the blue one I believe 0 221 121 00. Timing is good and dwell is at 36, a little low but still within the 38 +- 3.

I previously had a '71 MB coupe that also had carbs and would start up immediately hot or cold. I would like to get to that point so am looking for help in where to start and what to check for. Please ask questions if you need more info.
Many thanks.

[Norm01]

Turn the key on first and then pump the gas, pumping the gas with the fuel pump off wont give you fuel delivery.

[Irish911]

Norm01, thanks that did help a lot. Tried it this morning and the engine caught right away and idled longer before dying. Restarted and while it is certainly better than previously, I still have to tap on the gas every 5 or 10 seconds to keep it running. It takes much less time however to get it to finally idle without dying. Is there anything else I can do/adjust to get it to fire and keep running? I still get some hesitation initially when it has started cold.

When hot I am reluctant to tap the gas before starting in case I flood the carbs. Is this correct?

I have read somewhere that the CDI unit should whine when the car is running. Mine does not make a sound. It was recently replaced with a reman unit as the previous one was toast I was told.

[yale]

Is the throttle lever attached?

[Norm01]

Holding the rev's near 2000 for thirty seconds or so is normal, remember these carbs have no choke. It is also normal for the engine to take 5 minutes to warm up before it's really drivable. It took me a while also to learn how to hot start my 68, i start by cranking and if it doesn't catch I will depress the gas pedal a bit and if it doesn't go I push the pedal to the floor. Everything you've described seems quite normal to me, just the joys of old cars.

[Irish911]

Yale, yes the throttle lever is attached. I can see the accelerator move down as I lift the lever.

Thanks Norm01. I think not having the choke is thowing me. The carbs in the MB coupe I had did have an automatic choke. Glad to hear my experiences and not too abnormal. I have found that I do need to wait about 5 minutes for it to warm up before I go anywhere. Appreciate your help.

[blucille]

Yale, this car has carbs....

Coupe of things I've heard and practiced with great success

'Pumping the gas' when cold, after turning the key to the on/run position, you want to press the gas pedal to the floor and hold it there for a few seconds, loong seconds, release, press and hold again. This uses the acceleration pumps to get some fuel into the motor.

'Throttle lever' you want to leave it fully off until the car catches or starts running, this was you maximize the vacuum needed to pull the air and fuel into the motor. Once it catches or starts to run, as you feather the gas, pull the throttle lever up a little. Some say you should only pull up on the lever when your foot is on the gas, so you don't stress the plastic fork that activates the hand throttle. Never had a problem, but sounds like ok advice.

Warm starting.....it has been suggested, if the car has been run 'recently' (I'd say maybe the last 30 minutes) you want to start without pumping the gas, but with your foot mostly buried in the gas pedal, mostly or fully floored, and here's why. These cars are susceptible to carb fires due to boiling fuel being pulled into the combustion chamber, heat-soak is the main issue here....and I've heard of several cases very recently. So if the throttle is wide open, the flames will get drawn into the motor averting damage (hopefully).

[VaporiZe]

Check and make sure that the wires for the battery are not touching anything like the body of the car, that might be your problem for your car not starting up right away, as for it dying after a while I don't have a solution for that. It could just need a tuning, after the fuel emissions went up my dad had to get his 71 911e tuned to pass smog and it would stall idling at a light.

[Princess]

Here's my two cents:
Make sure you Accelerator pumps aren't clogged.
You should be able to take off your air cleaners
And look down your carbs and make sure
You can visually see gas squirting down the Throats
When you throttle them, Sounds like this is suspect
#1
Check your points and make sure there not pitted and Gapped correctly.
When in doubt change your points and learn to set
Them yourself so you know it's done right.
Max Advance your timing, If the above two are not the culprits.
I'm betting on bad accelerator pump but anytime she Dosent fire right up,
Advancing timing will help.(if points are set correctly
And accel pumps are working)
30 degrees BTDC @ 3000RPM Or what ever
Your motor/ Distributor spec is.
Good Hunting!

[laneranch]

My 71 T with stock Zeniths runs rough when I first start it but I engage the hand throttle just enough to keep the rpm up around 1500 and after a few minutes it is no longer needed.