Sticky throttle cable

[DanRemmers]

So after driving through the grid and paddock for an autocross that was cancelled due to lightning and torrential rain that washed some cones away, I found that my throttle cable was sticking at the next event two weeks later.

It is the stock throttle cable with flexible sheath in the engine bay and solid sheath (brake tubing) in the cockpit. Over the years, the rubber insulation had melted in two places near the motor, and water got in to cause rust. I have a NIB stock cable.

Question 1) How should I clean out the hard sheath in the cockpit? I don't know if it's stainless steel, so should I replace it? Is there a special lubricant that should be used? Should I use a grease gun to flush and lubricate?

Question 2) Should I keep the cable I have and just replace the flexible sheath? The stock cable will require modification at the ends and possibly for length.

Question 3) What should I use to protect the new cable from melting near the engine?

[Dietmar]

Dan:
Only thing worse than a stuck throttle cable is finding out you have no brakes going into a 90 degree turn. If it were my car I would change the cable AND the housing. Past experience with customers who have fried the housing is that the throttle suddenly sticks ( as in your case) and the only cure is to replace the cover. Why not run the housing from the back to the front? No need for grease, oils or... and rarely does it rust. If you want to be safe, a light grease on your fingers as you are threading the cable through the housing might keep it "lubed". Not a bad idea to change the throttle cable every couple of years anyway.

To keep it from happening again- if the cable housing is so close to the exhaust, reroute the cable or buy some insulation ( header wrap) and that should help.

Dietmar

[96vee]

dan,check your local motorcycle dealer for a cable luber. i've had one i bought a long time ago an it still works fine.it will look like a small box that surrounds the cable and you use what ever lube spray you have.it's a must have for dirt biker's and f/vee driver's.take care,billc.

[brian]

I use a 105" brake cable and universal housing which are available from any good bicycle shop. The housings are lined and do not need lubrication. Oiling cables just makes them attrack dirt and dust.

[DanRemmers]

UPDATE:

Last night I disconnected the cable from the pedal and the carb, and it moved freely. Then I noticed that each pedal had a grease fitting (is that stock VW?), and the gas pedal pivot was dry, rusty, and binding. So I greased it up, reassembled, and everything seems to be working fine now.

Of course it's possible that the cable was the problem all the time, and the tension from the throttle return spring will make it bind again. I'll drive it and find out. I'm going to the Bugout on Sunday, so a few passes on the 1/8 mile and a couple slalom runs should be a good test.

Do I need a return spring on the gas pedal? It's probably not necessary, but may be a good safety device.

[Mad Dog Racing]

Per the GCR, you need two return springs on the throttle linkage. About 99% of the time that means on the carb, not sure tech would accept one on the pedal as one of the two. Not sure what the rule is for solo, usually it seems to be the same, but I've seen one get by. A spring on the pedal doesn't do any good if the cable breaks. The shifter kart has an internal spring in the carb so the return spring is on the pedal just to give it some feel.

[FV80]

Per the GCR, you need two return springs on the throttle linkage...

Mike - I'm not aware of any such rule and can't find it in the GCR. Is there REALLY such a requirement? And, if so, where would I find it in the GCR? Not to say it isn't a GOOD IDEA! - just wondering about a RULE ( *I* would be immediately illegal! hmmmm... maybe not... I could count the accelerator pump return spring as ONE <G>).
Steve

[jpetillo]

Hmm, I know I read it last year in the GCR. But I just did a quick search and didn't find it.

John

[Mad Dog Racing]

Steve,

You got me on that one, sorry to spread any mis-information. That's what I get for talking before thinking.

Possibly was put on me by someone in tech when getting an annual. Looked back at an '07 GCR, a '94 GCR and my original '84 GCR and none said anything about throttle return springs. The most likely place would be the list of items to be checked by tech, it goes right down the list - and no springs on the carb mentioned.

The '86 Solo Rules says "Throttle return action shall be safe and positive." So maybe I picked it up back when I was running solos. Or maybe it's a SowDiv thing. Two FV's and a FF I have bought locally over the years all had two return springs as far as I remember. I've only bought one "new" vee and it was a roller needing finish work aft of the roll hoop, I put on 2 springs.

[dd46637]

The Tech people seem to encourage the use of 2 return springs on the carb but I have never found a direct rule stating that it has to be that way. After my stuck wide open throttle experience this weekend at Grattan you can bet there will be 2 on there the next time!
Dave

[fv87]

I know this thread is old, but I had problems 2 race weekends recently. The first one ended in a spin out and crash when the car wouldn't slow down after a straight.

The 2 springs are at the carb to make sure the thottle gets cut back if the cable breaks. I do believe I saw it in the GCR somewhere. I even came across it when I was prepping an FSP car.

I replaced it all with a nice cable, sheath and nylon insert from pegasus.