1972T hand throttle question

[Dourobot59]

Hi folks
New to me 72 hand throttle doesn’t do anything so I have a question.

Photo 1 shows linkage by bell crank with throttle lever down.
Photo 2 shows linkage by bell crank with throttle lever up.

This winter I plan to replace bushings and clean/lubricate all the linkage (and get rid of the spring that was added) but in the meantime is there an adjustment I can make to get the handle throttle to work?
Thanks

[Dourobot59]

Photo 1 on bottom, photo 2 on top

[blucille]

Chances are, the trouble with your hand throttle is inside the car. Typically the white plastic lever that moves that throttle rod, turns brown and disintegrates. Once in a while the metal ferrule on the rod just needs to be moved back into position.

Still, once you take it apart, you might as well put in a new plastic lever.

Pretty easy to do, some guys remove a seat first but you can get it with both seats in place if you want.

[E Sully]

Plenty of information in this thread.
Hand throttle lever

[Walt Fricke]

Yes, you were looking in the wrong place. Remove what you need to remove (on my car, the hand brake assembly) to get at the bottom of the hand throttle lever.

[RWebb]

and de-rust all that area in the pics

[HarryD]

As noted above, it is extremely likely the plastic part that moves the throttle rod at the black lever has disintegrated. You will need one if these: 901-424-317-00-M100. With some contortionism it took me 2 hours to replace.

Also the extra spring may have been added since some HPDE and racing groups require two throttle return springs so for our early cars, we have to kludge something. I had to do the same thing on my car. I drilled a hole in the bell crank lever arm so the spring was not rubbing between the ball and the lever arm.

[Dourobot59]

Hi folks,
Finally got looking in the tunnel and found that the plastic piece is good (see photo).
I will need to do some adjusting on the metal ferrule to take out some of the slack/play in the pedal.
Thanks for the responses and pointing me in the right direction.
Larry

[john walker's workshop]

Just loosen the screw enough to move the aluminum piece along with your screwdriver in the set screw slot, then tighten. Otherwise it drops in the tunnel. Yippee.

[Dourobot59]

Thanks for the tip

[proporsche]

also, adjust the link from trans.to to engine too much play in it..
Ivan

[blucille]

Keep in mind, the slack is probably there for a reason. It should be set that even when the car is fully warmed up, the idle cannot go above 2000 rpm

[donlan]

Hello, The plastic bit was disintergrated in mine and I made and fitted another one.....somehow. Donlan. I have engine no.6124238.

[tobluforu]

I had one of those springs. It works well when linkage/bushings and your stacks (sticking) aren't working well. Take it for a cruise, then unhook it and see if idle changes. One thing you will definitely notice is how much easier it will be to press the gas pedal.

[E Sully]

Originally Posted by blucille

Keep in mind, the slack is probably there for a reason. It should be set that even when the car is fully warmed up, the idle cannot go above 2000 rpm

The correct adjustment is higher. It is not so much that Porsche wants the car to run at 4,000 rpm, but that the throttle plate is opened up to a certain point when cranking, and then lowering the hand throttle incrementally to keep it idling till warmed up. Don't forget the micro switch adjustment. From the thread I posted above.

Originally Posted by E Sully

According to the Haynes book for the 1973 cis, 4000 rpm. You should use a sturdy needle nose and it is a standard slotted screw. Try a quarter of an inch towards the rear to bring the rpm up.
Also, you should check the micro switch on the throttle body is operating properly.

[eastbay]

Surprised nobody has made an aluminum copy of the plastic part, I know I would be a buyer.

[RWebb]

the plastic is supposed to be flexible - they harden over time, then break

[HarryD]

Originally Posted by eastbay

Surprised nobody has made an aluminum copy of the plastic part, I know I would be a buyer.

why? The plastic part lasts for ages and replacements cost $21.17 from Porsche and $16.75 from URO. Not sure a bespoke part can complete at that price point.

[Dourobot59]

Ok, I managed to get in there and move the adjustment nut closer to the white plastic piece. I didn’t drop anything!

Started the car and pulled the lever up while pushing accelerator pedal. It works and tach is holding at 3,000rpm with lever all the way up.
Engine idles down to 900rpm when I push the hand throttle all the way down.

Looks like the linkage at the transmission bell crank is now sitting where it should be when the handle throttle is in down position? See photo.

Thanks again to everyone for the responses.

Rust clean up on list for when the snow flies here and car is parked.
Larry

[john walker's workshop]

A little grease on that loop keeps it from wearing through.