Occasional sticking throttle

[tforturton]

This evening I got stuck in road works, and out of nowhere, the throttle started to stick, at about 1500 or 2000rpm. If I blipped the throttle, sometimes it went back down to normal, other times just went straight back to 2000rpm, and on one memorable occasion, it dropped back down to normal, then crept slowly back up to 2000rpm. I got to my destination (football training), was there for an hour, then had the same journey home - but with no road works - and no throttle problem. Went out later for a short drive to collect a bike, again, no problem. This happened once or twice before, a long time ago, but then it was only once or twice then it settled back down to normal. This time it was continuous for fifteen minutes or so whilst I was moving in very slow traffic. I switched it off a few times, but each time it went back to sticking at about 2000rpm.
Any ideas? Frayed cable? Throttle return spring? Carbs spindles?

[kevtherev]

You got this 2.1 on a Pierburg?

[rockthebus]

This is bizarre. Mine did exactly as you describe yesterday and the day before. Seems to be when it's all thoroughly heat soaked. Was OK today.
2.1 injection SS

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[tforturton]

You got this 2.1 on a Pierburg?

Er, no....I've still got the fuel injection, so please disregard me rambling on about carb spindles.
rockthebus seems to have had a similar problem - yes, it was when the van was running hot. Coil need relocating?

[rockthebus]

Since ambient temps are now cooler, mines been fine. Has yours?

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[StefG]

When mine was doing this a couple of years back it turned out to be a frayed throttle cable. I would be able to lower the revs sometimes by hooking my foot under the pedal and lifting it up, sometimes though the pedal would pop off the linkage. When I got round to changing it I lubed up the whole linkage, no issues since

[GrahamL]

Hi,
I seem to get this when changing gear; I first thought I was accidentally keepin my foot on the throttle, but found the revs increased as I dipped the clutch to change gear, with the revs dropping as I moved into a different gear.
Regards
Graham

[StefG]

That sounds exactly how mine started misbehaving, check the throttle cable runs freely.....

[tforturton]

A year on, and this weekend, it happened again. I haven't changed the cable since this time last year, mainly because I've had no problems with it, up until now. I don't do a huge amount of miles, just out and about around town a few days a week, but I have done a few 50-mile trips - all with no problems. The circumstances were the same as last time - I was queuing in slow moving traffic - so it's linked to engine temperature. It definitely wasn't over-heating, the fan kicked in as normal, but I still had the sticking throttle. And it doesn't stick wide open, but appears to stick at about 2000rpm.
Any ideas, or should I really think about changing the cable? Alternatively, is there any way I can lubricate it?

[kevtherev]

Yes it can be lubed once off.
Pretty easy.
I think its right that you eliminate the small stuff first.
If it doesn't fix it then you can move on to more expensive things

[captain Byrne]

Got the same problem with my 2e3. All ok when cold but it starts sticking when warmed up. I've found that if I spray WD40 on the spindle return spring it temporarily solves the problem. It returns after a hundred miles or so. Needs a strip down & clean I guess.

[CJH]

Got the same problem with my 2e3. All ok when cold but it starts sticking when warmed up. I've found that if I spray WD40 on the spindle return spring it temporarily solves the problem. It returns after a hundred miles or so. Needs a strip down & clean I guess.

On the 2E3 there's a chance that this could be caused by the accelerator pump cam jamming behind the accelerator pump lever. If the gaskets below your carb are a bit thin, and/or if there's a lot of muck on top of the inlet manifold, the end of the pump lever can make contact with the manifold, and the cam can push past the lever and get jammed. If it's this, get in there with a screwdriver to clear some of the muck off the manifold where the lever makes contact.

[captain Byrne]

Thanks CJH - will have a look at that.