hand throttle vs cold start circuit, Anyone use the CSC on Webers? Options

[bbrock]

My Webers have the cold start circuits installed. While I'm replacing the floor pan and have easy access to the tunnel, I am thinking about adding a couple tubes to run cables from a hand throttle lever to the carbs to operate the chokes. Wondering if anyone has done this and whether it would provide superior cold starting to the traditional hand throttle. I live in the frigid north where it can freeze any day of the year, so I want the best cold start operation I can get. Thoughts?

[GeorgeRud]

The original hand throttle just provided another way to depress the accelerator cable on the -6s. Please post pics of your Weber carbs with the chokes - I assume they’re not for a -6 as I’ve never seen chokes on the 40IDA or IDT carbs.

[bbrock]

The original hand throttle just provided another way to depress the accelerator cable on the -6s. Please post pics of your Weber carbs with the chokes - I assume they’re not for a -6 as I’ve never seen chokes on the 40IDA or IDT carbs.

Oh yeah, I should have added those details. These are 40IDFs for a 4 banger. Seems everyone using these with air cooled engines either ignore them, or block them off because engines start cold without using it. But 95% of those people live in Cali so.....

Here's a pic of the cold start on one of my carbs. The circuit adds a little extra fuel to richen the mix rather than reduce air like a traditional choke. Seems like this would be better than than just bumping up revs with a hand throttle until the engine warms. (IMG:style_emoticons/default/confused24.gif)

[porschetub]

No not really needed a handthrottle is a better solution,getting the cables setup correct would be a hard task,last thing you need is one to stay open a bit and fuel wash your motor.
I remember an old article on the Porsche 356/ 912 about why they had no chokes on the these cars the reply from Porsche was something like ''parts you don't need'' .
On my six its 3-4 pumps on the accelerator hand throttle full on and it starts right up,not long before you pull the hand throttle back to idle,if your carbs are dialed in you will have the same result with a 4.
Good luck (IMG:style_emoticons/default/beer.gif)

[DaveO90s4]

My 914 as purchased with its single centre mounted carb was very hard to start. That carb had a choke arrangement that was disconnected.

To connect it I simply ran a cable from engine, through centre of firewall low down about where the other cables , fuel line etc go through, horzontally out the small access hatch between the seats near the firewall, along the right hand slider of the driver's seat and made a small bracket to mount the cable pull lever on to the front R H seat, down close to the floor.

Worked perfectly, no horrible cable kinks, unobtrusive, easy to manipulate, no dashboard modifications, etc

I know you obviously have different carbs, but if you do decide to connect a cable you might find the above the easiest way to do it.

Regards

DaveO
Oz

[nditiz1]

Mine did have the CSC hooked up on both carbs. I will most likely not use it as I am trying to clean up the engine bay.

The PO was into bicycles and used a hand lever hooked to a central mount point. There was a bracket mounted at the rear of the engine on the top. The cable inside would pull both levers open all via bicycle brake/gear cables. It was a pretty neat setup. PM if interested in having my old setup. The lever was mounted just behind the E-brake, but could be mounted anywhere really.

[bbrock]

No not really needed a handthrottle is a better solution,getting the cables setup correct would be a hard task,last thing you need is one to stay open a bit and fuel wash your motor.
I remember an old article on the Porsche 356/ 912 about why they had no chokes on the these cars the reply from Porsche was something like ''parts you don't need'' .
On my six its 3-4 pumps on the accelerator hand throttle full on and it starts right up,not long before you pull the hand throttle back to idle,if your carbs are dialed in you will have the same result with a 4.
Good luck (IMG:style_emoticons/default/beer.gif)

This seems to be the consensus and helps answer the first questions of whether it is needed. What would be a typical "cold start" air temp for you? I won't be driving the car much during winter so starting in our -35F/-37C temps isn't much of a concern, but there will be plenty of days starting the car as low as 0F/-17C. Part of my challenge is figuring out if no-choke starting experiences of others translate to Montana weather.

My 914 as purchased with its single centre mounted carb was very hard to start. That carb had a choke arrangement that was disconnected.

To connect it I simply ran a cable from engine, through centre of firewall low down about where the other cables , fuel line etc go through, horzontally out the small access hatch between the seats near the firewall, along the right hand slider of the driver's seat and made a small bracket to mount the cable pull lever on to the front R H seat, down close to the floor.

Worked perfectly, no horrible cable kinks, unobtrusive, easy to manipulate, no dashboard modifications, etc

I know you obviously have different carbs, but if you do decide to connect a cable you might find the above the easiest way to do it.

Regards

DaveO
Oz

Mine did have the CSC hooked up on both carbs. I will most likely not use it as I am trying to clean up the engine bay.

The PO was into bicycles and used a hand lever hooked to a central mount point. There was a bracket mounted at the rear of the engine on the top. The cable inside would pull both levers open all via bicycle brake/gear cables. It was a pretty neat setup. PM if interested in having my old setup. The lever was mounted just behind the E-brake, but could be mounted anywhere really.

Whoa! Two guys who have chokes/CSC hooked up! I've done a lot of searching on this subject and you guys are the first. Nice to hear it can actually work. Bicycle cable (or frunk cable) is exactly what I have in mind. Difference is that I'd run the cable to a 914rubber repop lever mounted in front of the gear shift for a factory appearance. I think it would be simple and reliable. Actually, I think it would be easier than retrofitting a hand throttle since it wouldn't require a mod of the peddle cluster. The bigger questions is whether it is necessary.

[theer]

I had a hard time starting my 1.9l w/ dual 40 webers this weekend. Temps were in the low 40's (F). It finally started, but it took a few minutes.. maybe 7 -10 crank attempts?

Choke would have been very helpful.

So - do I have this circuit already, or is it an add-on? Is there an electric choke available, like on the old VW's?

[Tbrown4x4]

None of my 40 IDF castings are not even machined for the enrichment circuits.
It gets cold here, (not Montana cold) but a few pumps and off she goes. I hold the idle speed up with the pedal long enough to start defrosting the windshield and I take off.

[Tbrown4x4]

The IDF's don't have choke plates or a mechanism for fast idle speed. The enrichment circuit just supplies extra raw fuel for a cold engine. Much like a lot of older motorcycle carbs. (I'm thinking Mikuni's, I believe a lot of Keihins have choke plates.)

[bbrock]

So - do I have this circuit already, or is it an add-on? Is there an electric choke available, like on the old VW's?

Like Tbrown4x4 said, it depends. Some have them, and some don't. If yours have a mechanism like in the picture above that has a little lever a cable would attach to and a brass screened intake on the bottom, then you have it. If you have a solid plate screwed on there, then you could probably easily add it. Since most people who have them, take them off, I'd think they'd be easy enough to source. But I still have no idea how well they work.

[Tbrown4x4]

Most people disable them by tapping the casting for screws to hold the plungers down. The problem with them is they can stick and dump raw fuel into the intakes. I always wanted to have the enrichment circuits, but honestly never really needed them.

In reality, fuel injection is your best bet for all situations, but it sounds like you're already set with the carbs.

[bbrock]

Most people disable them by tapping the casting for screws to hold the plungers down. The problem with them is they can stick and dump raw fuel into the intakes. I always wanted to have the enrichment circuits, but honestly never really needed them.

Hadn't seen that trick. But I've seen these block off plates.

In reality, fuel injection is your best bet for all situations, but it sounds like you're already set with the carbs.

Well, that's a story I just wrote about on another thread. I tore this engine down for rebuild in 1989. A large reason was because the FI had become an unreliable POS and I had no idea how to fix it. Everyone was putting carbs on back then, so I rebuilt the bottom end with a carb cam and bought the IDFs. Twenty-eight years later and I'm finally finishing the project. Eventually, I'll likely go back to the FI but for now, it will be these carbs.

[porschetub]

No its not really that cold in winter @ my part of the world,I think your best option is test them once you have your engine together on a cold day ...if it starts better set them up with a 2 way cable,I would be worried about forgetting to close them after warmup however (IMG:style_emoticons/default/sad.gif) .
IMO a well tuned (jetting,ignition and cooling system ) aircooled engine will start up easily in most conditions without a choke.

[Spoke]

My 2056 has dual carbs and starting it is not too much trouble. Got to pump the throttle a bit to get fuel in the chambers first. The first attempt doesn't start the car as the carb bowls fill with fuel (after sitting for a week +) before it will start.

I do find that the engine hesitates off the line quite a bit before it is warm w/o a choke with carbs. Much more obvious in the cold weather as opposed to summer temps.

[Tbrown4x4]

My car doesn't sit very much, but I put a fuel pump controller in that runs the pump for 3 seconds and then waits for a tach signal. (I have a CB performance 3.5psi pump near the 75-76 location.)

[Elliot Cannon]

My fuel pump (CB Peformance 3.5psi) comes on as soon as the key is turned. When it's cold I turn on the key, pump the throttle a few times and squirt some fuel in and it starts up great. I don't too often operate in below freezing temps but when I do, I use the same procedure. Works great for me. (IMG:style_emoticons/default/smile.gif) I never felt the need to hook them up.

[bbrock]

This is all great feedback. Still would love to hear about starting a carbed engine at zero degrees F, but this has been great. I'm liking the idea of just waiting until the car is back together and testing the cold start circuit. I was thinking that the time to prep for cables to the carbs would be when I had the floor off and tunnel opened up. But in reality, it's just a couple holes with grommets that would be needed to pass the cables through the firewall.

As for forgetting to put the lever down after the engine warms, I wouldn't think it would be much different from a manual choke. It happens, but becomes obvious pretty quickly. In this case, I would assume the engine would idle fast due to the rich mixture.

One other thing. In addition to starting ease, I've read elsewhere of some people warning about fuel washing the oil off the cylinders when you pump the accelerator just prior to starting. That might just be crazy "Internet lore" but wonder what you think. It is true that the cold start circuit would be spraying atomized mix into the intake and only when there is vacuum to pull it in during a combustion cycle.

[jd74914]

As for forgetting to put the lever down after the engine warms, I wouldn't think it would be much different from a manual choke. It happens, but becomes obvious pretty quickly. In this case, I would assume the engine would idle fast due to the rich mixture.

Yeah, you'd hit a high idle. As a note, my dad drives his carbed 911 when it's well below freezing and I don't think has ever forgotten that lever so once you get acclaimed it's really a non-issue IMHO.

One other thing. In addition to starting ease, I've read elsewhere of some people warning about fuel washing the oil off the cylinders when you pump the accelerator just prior to starting. That might just be crazy "Internet lore" but wonder what you think. It is true that the cold start circuit would be spraying atomized mix into the intake and only when there is vacuum to pull it in during a combustion cycle.

Ehh, really no different than a cold start value or the increased fuel pulse on a FI car. You know, in a really cold start on a modern car they actually can inject 100-1000 times more fuel per pulse then needed at idle and don't have washing issues. At those temperatures your fuel is condensing on the intake manifold and almost dripping into the cylinders at low engine speeds to I really don't see much different. You'll get pooling no matter what.

[bbrock]

Ehh, really no different than a cold start value or the increased fuel pulse on a FI car. You know, in a really cold start on a modern car they actually can inject 100-1000 times more fuel per pulse then needed at idle and don't have washing issues. At those temperatures your fuel is condensing on the intake manifold and almost dripping into the cylinders at low engine speeds to I really don't see much different. You'll get pooling no matter what.

Wait... what? Are you saying that people on the Internet make (IMG:style_emoticons/default/stromberg.gif) up? This changes everything! (IMG:style_emoticons/default/blink.gif)