What is the Hand Throttle for?

[svonkampen]

Silly question i'm sure.......

But this is my first Porsche and my books don't say what it's for>>>

The lever to the left of the hand-brake....What does it do?

Svk
1968 911L

[john walker's workshop]

keeps the rpm up so it doesn't die during warmup. there is no choke, and no automatic fast idle system on those cars. 1200-1500 at first, then bump it down as the engine warms and wants to idle better. it works the same linkage as the throttle pedal.

[Tyson Schmidt]

It just gives you a high idle. It's not a choke, and has no effect on mixture. Works great as a cruise control on long trips to rest your right foot!

[Porschekid962]

i use it to make my dad drive faster!!!!

[bigchillcar]

the hand throttle was only available for a year or two. it literally is, as john mentioned, a link to the very cable cable that runs from the accelerator pedal all the way back to the engine. if you look carefully, you will see that pulling it up all the way will cause downward movement at the accelerator pedal.

the manual specifies that this handle should be all the way in the full up position for starting. after start, like john says, adjust idle to around 1200-1500 until close to operating temperature. then you can have it all the way down, as it's no longer doing anything necessary.

couple notes...there is a cheap piece of plastic in the tunnel underneath the handle which often breaks. if your handle appears to do nothing (which you didn't say), it's likely that this piece which links the handle to the actual cable has broken...or it's out of adjustment. there is a screw adjustment in there, simple device, it just moves the position of this piece of plastic, so that full up will produce a high idle (~2000-3000) on initial startup.

that shpuld about cover it...
ryan

[SandyI]

Raise the hand throttle to its maximum height before turning the ignition when starting your car from cold.

[Zeke]

I don't think it was available for only "a year or two." I believe all MFI cars have them. I can think of 4 years right there.

As far as pulling up all the way, that makes mine rev pretty high right at start up. Like 3 grand. I push the pedal down 1" and start. Once running, I set the throttle to where it helps keep the revs up so it doesn't stall. This is handy if you drive off readily and need to use the clutch and brake. I've usually got the engine settled down a bit before I go. The S cams are a bit snotty when cold.

[Joe Bob]

Poorman's cruise control.....

[bigchillcar]

I don't think it was available for only "a year or two." I believe all MFI cars have them. I can think of 4 years right there.

ahhh...i didn't realize the mfi cars had it as well. yep, sorry zeke. at any rate, the procedure i outlined was actually intended for a cis car anyway...
ryan

[SandyI]

With my MFI, I raise the handle all the way up and let the MFI run for about 30 seconds before I hit the ignition. Once it turns over and the revs begin to climb toward 3000, I immediately lower the lever down.

[Zeke]

Originally posted by bigchillcar
........... yep, sorry zeke...........

Hell, don't be sorry. I wasn't criticizing, I just wanted the guy to know that he has a fairly common item.

At least 2 here use it as a cruise control. Beats a stick, I guess.

[HarryD]

Originally posted by Zeke
I don't think it was available for only "a year or two." I believe all MFI cars have them. I can think of 4 years right there.

As far as pulling up all the way, that makes mine rev pretty high right at start up. Like 3 grand. I push the pedal down 1" and start. Once running, I set the throttle to where it helps keep the revs up so it doesn't stall. This is handy if you drive off readily and need to use the clutch and brake. I've usually got the engine settled down a bit before I go. The S cams are a bit snotty when cold.

Zeke, you are quite correct, my '73 with CIS has one as well. In addition to opening the throttle plate, it activates the 7th injector to richen the mixture a bit to help the car start.

For my car, starting it cold is sort of a dance:

Pull up the handle, crank, push handle down, crank some more, let the engine catch, move handle up to increase idle to 1500-2000 rpm and after a few minutes, cut it back to 1200 rpm, drive off. As the car warms in the next 3-5 minutes, slowly push the handle down to keep rpms at 1000+ or so until it is fully turned off.

[Loual]

My '75 has a hand throttle as well. I forget what the last year of the hand throttle was, but I don't believe SC's has them (78-83).

[RMartin]

My 68S with carbs has a lever to the left of the handbrake also. Is it used for the same thing?

[PorscheRB]

mine is pretty sensitive, at idle it'll bring it almost to the redline. It's useful for several things:

1. the usual, boring, warming up in cold weather

2. cruise control: all the way up = 80mph

3. it allows you to rev your engine at the same time as you have your foot on the brake, thereby allowing you to impress chicks while doing things that occupy your right foot, like braking or stomping on some ricers.

[palle7688]

The hand throttle is acting on the throttle linkage in the tunnel, which is a thin steel rod. It does the same as the accelerator.
It has nothing to do with 7th injector (it's controlled by the warm running compensation control pressure regulator)(on CIS/jetronic engines)
On the throttle linkage there is a nipple with a setscrew. The nipple should be adjusted so that when hand throttle is fully "open" engine speed is between 3500-3800 rpm.
I've to admit I've adjusted mine so it's possible to give close to full throttle by hand, but I don't need to raise idle at cold since I've motronic 3.2l installed.

[svandamme]

anybody has a schematic of the hand throttle linkage

i'll be attempting to fix mine, and last time i looked at it , all i saw was lot's of grease , and dirt... so i'm not sure how to put in the new piece of plastic...

[Jgordon]

PorscheRB, does that mean you could use it as an alternative to heel-and-toeing?

[HarryD]

Originally posted by palle7688
The hand throttle is acting on the throttle linkage in the tunnel, which is a thin steel rod. It does the same as the accelerator.
It has nothing to do with 7th injector (it's controlled by the warm running compensation control pressure regulator)(on CIS/jetronic engines)
On the throttle linkage there is a nipple with a setscrew. The nipple should be adjusted so that when hand throttle is fully "open" engine speed is between 3500-3800 rpm.
I've to admit I've adjusted mine so it's possible to give close to full throttle by hand, but I don't need to raise idle at cold since I've motronic 3.2l installed.

Err.... I may be mistaken but I ahve always thought that on a 73 1/2, the injector is controled by a microswitch activated by the hand throttle.