Tips needed for starting carbureted 911T in cold weather

[supersignman]

This is my first winter with my carbureted '69 911T and I need the magic formula on how to start it in cold weather. I live in Alabama so it doesn't get extremely cold here but we occasionally have nights where temps get below freezing. This is my first experience with chokeless carbs in cold weather so I thought I'd see if anyone knew the perfect timing and sequence of pumps required. I ended up flooding it so badly yesterday morning that I had to give up and drive another vehicle. Unfortunately I caught some serious grief when I got to work about not being able to start my "overpriced Bug". It's difficult to get any respect for fine German engineering here in the land of NASCAR and this situation certainly didn't help!

[OldSpool87]

Can’t help you with the issue at hand, but I can give your thread a bump and tell you that sure is a pretty car.

[supersignman]

Thanks OldSpool 87! I like to think of my car as Old School Cool!

[jlex]

Can't say I've ever owned a car with a chokeless carb so I can't advise you on starting.
If you flood it, however, you can dump that excess gas by holding the accelerator pedal all the way to the floor while cranking (don't pump the pedal any more) Doing that will dump the excess gas. Leave up on it as soon as it starts to prevent over-revving.

[Charles Freeborn]

Couple of pumps, then hold at 1/3rd throttle until it catches. If it stutters (almost starts) it will have burned off the "prime" so another short pump. If it floods, as said, hold throttle to floor (without additional pumping) to give it a gulp of air. When it does catch hold idle to 1500-2k while gently "massaging" the throttle (give it little squirts from the accelerator pumps) until it smooths out and idles on its own.

PS if it has been sitting long enough for the float bowls to go dry you'll have to turn the key to on, let the fuel pump run for a few seconds to fill the bowls, and then begin start procedure.

[jlex]

No automatic choke on the carb? Never heard of that.... I suppose you could always buy a manual choke set-up. Plenty of cold weather in Germany, so it's hard to imagine they wouldn't have made provision for a choke.
BTW, beautiful car. Reminds me of the white T my brother in law and I would tool around in back in '72.

[kent olsen]

Webers on my 72 for 20+ years.

Like Charles says: I do two pumps which doesn't quite catch then two more with the throttle just open and that catches it. Then hold the idle about 1500 for a minute. '

If you have the hand throttle set it about 1200 as it warms up. After a couple minutes you should be good to go.

[icarp]

Each car is different in it's need for fuel to start, first what is the temp? The colder it is the more fuel the engine will need . 35 degrees +- 5 is a good place to start. The carbs have accelerator pumps ,
they squirt raw fuel directly into the intake port . If I were to make my first attempt to start the car my steps would be , 1 , three slow pumps to the floor , about 3 seconds of pump per stroke .
2 , no throttle , turn key to start, what happens ?
starts and runs ? all is good note the temp and pumps in the brain log . or coughs and spits ? then tickle the throttle with 1/2 inch rapid pumps, ahh that did it it is running just give it a tickle when it wants more fuel to keep running , let it warm up 1-2 min, no start just cranking , 2 more full slow pumps , no throttle and crank the engine , starts ? use first steppes to keep it running and warm it up. No start at all, Hold down the throttle to the floor for 2 minutes , evaporating the fuel,
Then crank the engine holding the throttle to the floor , when it fires keep the throttle down until the reves hit 1800-2000 rpm then back off on the throttle , if the temp is colder then one more pump, really cold then 2 more pumps , not so cold fewer pumps , that should get you started
Ian

[kent olsen]

Oh, and I have dual Carter AFB's (aluminum four barrels) on my Hemi/Vette also with no choke. Same technique .

[supersignman]

Holding the throttle 1/3 of the way to the floor may have been the part I was missing. I've flooded it before in warm weather and the wide-open throttle position was the solution but even that wouldn't work the other morning. Once the car cranks it runs great even in freezing weather but getting it to fire off is the issue.

I guess I'm a little confused as to when the first two pumps should happen... before you start cranking or after? All the other cars I've had with carbs had an intake plenum so there was somewhere for the vapors to "hang out" before cranking but with these carbs shooting straight into the intake runner they certainly seem more sensitive on the initial start.

Another thing that's strange about this car is that it seems like it's either firing on all six or not firing at all. Other cars I've had with carbs would seem to sputter on at least a couple of cylinders before cranking on cold mornings but this one is either "on" or "off". If you have to hold the throttle wide open to crank it you'd better be ready to get off it quick because it will go from zero to 6K rpm in about half a second!

[jpnovak]

My method.

turn key on and allow pump to run for 5 seconds. If you have stock Bosch 3 port pump you might here fuel/air bubbles gurgle into tank as system primes.

Then pump throttle 2X 1/2 pedal and hold half way down. Wait approximately 3 seconds for fuel to start to evaporate (liquid doesn't burn well) and crank engine. As soon as it begins to fire you will likely have to use your foot to put very small squirts of gas from the accelerator pumps. The engine will stutter and you have to keep the car running. AFter approximately 10 seconds you should be able to pull the hand throttle and hold the engine above 1500rpm. The rpm will steadily increase as it warms over the next 30 seconds. Lower the hand throttle and maintain around 15-1800 rpm. try not to let it go higher with cold oil that has not circulated.

On first drives. Keep the rpm below 3500 until the temperature needle moves and comes off the "floor" of the gauge. Then slowly add rpm as the needle rises. This will prevent premature wear.

Oh.. Your hand throttle is working? Right?! If not, get it fixed. Usually its just a broken plastic drag link.

[supersignman]

Thanks jpnovak. I also wasn't waiting 3 seconds for the fuel to evaporate. I do hear the fuel pump gurgling and I usually wait for it to slow down before cranking. And my hand throttle doesn't work. I need to look into it. That really hasn't been an issue though. Once it cranks it doesn't take more than a couple minutes until it will idle fine.

[ChrisHoover]

Originally Posted by jlex

Can't say I've ever owned a car with a chokeless carb so I can't advise you on starting.
If you flood it, however, you can dump that excess gas by holding the accelerator pedal all the way to the floor while cranking (don't pump the pedal any more) Doing that will dump the excess gas. Leave up on it as soon as it starts to prevent over-revving.

Thats the technique my old man taught me to start my grand dad’s 66 Chrysler when I flooded it. Of course he strongly suggested in the way known to everyone with a cranky old man that I shouldn’t flood it in the first place

[bobb169]

Never had a problem..... have started mine into the teens... Couple pumps on pedal, crank, when starts to fire couple light pumps, feathering till starts.... have Zeniths... but each engine is different.

[T6andT]

I think the boys above have it right, to me very important that the pump is on for a few seconds to fill the bowls, especially with the new fuels. I pump three times and it fires right up, need to feather the throttle for about 20 seconds and then I am good to go. If this does not work make sure you are getting the proper amount out of the squirters and float level is correct.

[RarlyL8]

My method was completely different on my old '73 with Webers. Let the pump run for a couple seconds then hit the key while lightly stabbing the throttle as fast as I could. Fired immediately and sounded like a sprint car when it was zero outside. The throttle response was incredible!

[supersignman]

OK, thanks RarlyL8. I have Webers on mine also so I'll try that too. The old tried and true method of two pumps before cranking definitely isn't working. I know up on the mountain in Huntsville it can get pretty cold in the winter.

[VFR750]

Originally Posted by bobb169

Never had a problem..... have started mine into the teens... Couple pumps on pedal, crank, when starts to fire couple light pumps, feathering till starts.... have Zeniths... but each engine is different.

Yup. Same here. No hand throttle.

Fuel Pump on for 5-10 second to fill the bowls

Two full pumps of the throttle, pause,

start and Blipping throttle to pump fuel via the acceleration circuit for maybe 5 seconds.

Feather throttle to hold a high idle (2000 rpm) for 30 seconds.

Drive carefully until oil starts to warm. Don’t lug the engine or load it below 2000 rpm. Don’t zing it past 4000 until it’s warm

Btw, I cheat a little. I set my hot idle to 1100 rpm. Cold idle falls out to 800-900 and is lumpy for 3-4 minutes as it warms up.

Doing it this way for 10 years on Zeniths.