73.5 throttle return springs - which are correct?

[cak]

My throttle return is a big sluggish at times, so I ordered new return springs from our host. I started to install them this morning and was surprised to discover that the replacements are quite different than the originals.

The part description is very specific to the 73.5, so what's going on here? Was there a supercession? Or are these mispackaged?

The new spring is the leftmost of each pair:



For now, I left the old ones in place.

[Jim Sims]

What matters in this type of spring application is force and stroke capability and if the coil diameter/length will fit in the available space. Equivalent force and stoke can be achieved using different wire diameters, coil diameters and number of turns in coils. I wouldn't be the least bit surprised if Porsche changed spring suppliers sometime during the past 34 years. I'd install and use the new springs; they're likely much better than the OEM that surely have many cycles and probably corrosion/wear pits on the wire. Avoid using metal tools when installing the new springs to avoid nicking the wire or damaging the coating.

Another cause of slugginess throttle action can be worn or gummed up linkage pivot points and bushings, missing or hard bushings in the tunnel or a skewed/jammed rubber boot where the throttle rod enters the rear of the tunnel.

Also look for a rear parking brake cable against the throttle rod; the fabric straps retaining the cables can fail in time.

Cheers, Jim

[cak]

After several confirmations, I put the new springs in today. I only lost a little blood in the process

Vast improvement. In particular, the idle returns to 850 or so on a regular basis now, where before it would usually hover around 1100 no matter what I did...