another question

[jkirby4]

i am wondering what the "throttle" lever is for in between the seats. how is it used. sorry for such a basic question but this is my first 911 and i wanna learn. thanks

jim

[Oh Haha]

Glad to help.

It's for keeping the RPM's up while the engine is cold. Kinda like an old fashioned choke.


You may want to try to buy an owner's manual for your car. They come up on Ebay quite frequently.

I found a lot of useful info in the manual for my SC. The original was long gone when I bought the car.

[jkirby4]

i am keeping an eye out for one. thanks for the info

jim

[Paulporsche]

As Wayne said it's "kinda" like an old fashioned choke. The difference is it doesn't enrichen the mixture, as a choke would. It works the same linkage as your throttle (gas pedal) to hold the revs up. Put it all the way up for a cold start and leave it there. As the car warms up and revs stay @ the right level on their own, put the handle all the way down.

[robert walsh]

I have never seen one like this, what year and model is your car. In my 911SC, 1983 cabriolet, that lever is for operating the left side heater box, looks to me it may be the wrong knob put on your heat controll, on most the right knob is the right heater box and the left is for the left heater box. Never saw a throttle control, interesting at least.

[dshepp806]

Originally Posted by robert walsh

I have never seen one like this, what year and model is your car. In my 911SC, 1983 cabriolet, that lever is for operating the left side heater box, looks to me it may be the wrong knob put on your heat control, on most the right knob is the right heater box and the left is for the left heater box. Never saw a throttle control, interesting at least.

Interestingly, it is definitely throttle (notice the offset...)

Best,

Doyle

[Pazuzu]

Originally Posted by robert walsh

I have never seen one like this, what year and model is your car. In my 911SC, 1983 cabriolet, that lever is for operating the left side heater box, looks to me it may be the wrong knob put on your heat controll, on most the right knob is the right heater box and the left is for the left heater box. Never saw a throttle control, interesting at least.

It was 75, 76 or so when they got rid of the throttle lever. The defrost lever in those cars runs both flapper boxes together.

[RoninLB]

I installed the throttle lever in my two lever stock unit. I wanted independent driver/passenger heat.

The weak area is the plastic connection that moves the throttle cable. It gets stressed and eventually breaks. My routine is to use the foot pedal to increase the revs and bring up the lever to match the pedal.

It's not a complicated install.

I have pics if wanted?

[Poor-sche Lover]

He said on a different post that this is a '74.

[ossiblue]

Throttle lever was abandoned in 76 and replaced by (I think) the aux. air regulator and attatched plumbing--or something else that is thermo/mechanical.

The 74 also has a micro switch that is activated by the hand throttle to aid in the cold start--I believe it activates the cold start injector during engine crank. If your car has the throttle and it is in working condition (note Ronin LB's post), you really should use it to avoid unexpected back-fires from too much pedal on a cold start.

[Walter_Middie]

Ossiblue is correct. What hasn't been said here yet is that the lever is pulled up on every start. It turns on the micro switch. If the engine is cold, the cold start valve will run. If the engine is warm, the lever will only raise the idle. On my 1975, I only need about half the lever travel to start when cold. Then I ease it down to a comfortable "fast" idle. Once warm, I push it down all the way. If I start the car warm, then I only use the lever for a couple of seconds.

I like having control over the idle speed - no automatic controls to go wrong.

[Jim Sims]

From an old post:

The owners manual for a 1973.5 CIS states that the hand lever should be pulled fully up (so the micro-switch on the throttle body closes and sends power to the cold start valve) for all starts when the engine temperature is less than "very high". Very high is defined as an engine temperature of 212 to 250 F. Unless the engine is running hot and the stop is very brief (so the engine doesn't cool off) this in a practical sense means the lever is pulled up for every start. The manual further states that when the ambient air temperature is below -5F the lever should be fully pulled up and the gas pedal partially depressed; then when the engine starts, the lever is positioned for a 1200 RPM warm up speed. For "nominal cold starts" (air temp above -5F and engine oil temperature below 155F) the lever should be pulled fully up without gas pedal application and then once the engine starts the lever is lowered to set the engine RPM at 1200 for warm up. When the engine is warmed up (~155-160F oil temp) the lever is fully lowered. When starting a warm (as opposed to a "very high" temperature) engine the lever is pulled up for starting and immediately pushed back down after the engine starts. For the very high temperature case (212 to 250 F oil temperature) the hand lever is left down and the gas pedal is fully depressed during starting. It is important to note that the '73.5 and (also the 1974?) CIS cold start valve (CSV) circuits do not incorporate a thermal time switch so the driver has to control this function. Note though that as usual the CSV only operates while the starter is turning, it does nothing for cold running after that time.

Note that in some of these cars this lever may do nothing as an attaching plastic link to the throttle rod in tunnel may have broken or the micro-switch on the throttle body is broken, out of adjustment or disconnected.

[jkirby4]

it is a 1974 911. i was given the car and have no owners manuel so i am trying to learn as much about it as possible and get the car running.

thanks
jim