Last time I used the van in anger I found out that the tickover got stupidly high once she got hot. I have twin Weber carbs, not exactly sure which but I can post a picture if it helps. A couple of weeks ago I tweaked the throttle stop screws, one was screwed well in, the other wasn’t touching. I got the tickover nice and even but the van wasn’t hot, just warm from running on the drive. Today I went for a drive to a chippy in Mossley, and enjoyed fish and chips in the back of the van, I must remember to wash the knife and fork before the wife finds them. On the way back, as everything got good and hot, she started dying at junctions, then even in between gear changes. I put my spare gallon of petrol in, but that didn’t help. On getting home I got my 7mm ratchet out and screwed both throttle stop screws in a bit. I’m back to a reliable tickover when hot, no more cutting out, so I’m pretty sure that I’d overdone backing it off. It is a little ragged though, as if one carb is right on the edge of running right. I’ll try getting the plugs out to see if one’s a bit fouled, but not till it’s cooled down. I’ve never had the front plugs out, it looks marginal for room to get at them behind the carbs, but I’ll try my two piece 911 toolkit spanner. Any tips for getting the tickover spot on would be a help, obviously the manual is no help with this.
Behold, my setup Im not too sure I’m comfortable trying to balance the carbs for the first time without losing the setup altogether, but we’re off on a short trip away next weekend. What I don’t want to do is make it worse, it’s drivable at the moment but not 100%. On bikes I do it with borrowed vacuum guages. Do I need to take the carbs off to check they’re opening at the same time?
If it drives in a balanced way then the running balance does not need to be altered - that's the two long drop arms - you can leave them alone. Just adjust one idle stop until it's running as smoothly as it will then inch them to the idle speed you want?
I wonder how it got like that? If it can unscrew itself with vibration you need to address that first or you'll be wasting your time balancing them?
I think it got like that because I messed with it, when I bought the van from Ryan it ran fine, but the tickover sounded too high when it got hot.
It's why they invented chokes and cold idle throttle cams..and one reason I spent time and effort on learning to work with a Weber progressive. If the idle is right when it's hot you maybe have to nurse it when it's cold. Or it will be idling fast when it is hot if it's running nicely when it's cold. As it spends more running time hot than cold, set it up fastish for hot, but make sure it still runs cold. As it once ran nicely before you altered it put it back and accept a fast idle.. Then get hold of an air flow meter and set it up better when you have time and the risk is lower.
Which is odd because normally idle speed decreases when it's warmed up. Whereabouts are you? If you are near me I'd set them for you. Probably South-East as I'm North-West.
Not a million miles away (40), but the wrong side of Manchester - I'm near Burscough north of Liverpool. If you came here I'd sort them out for you though. More like £20, I have an extra that's not worth packing to send at a 2nd hand price, I'd end up with about 50p!
Thanks for the offer, I’ll do what Mike suggested for now, but if I can book us in for a night out in sunny Southport I’ll drop by, I may also look into what I can do with a meter. Carbs without chokes, no wonder it’s a balancing act.
All is much better, we went away this weekend and I had a usable tickover at the lights, without too much drama getting her to run from cold.
Hoo boy, it’s acting up again. I went out on a couple of errands today. The first short journey it started and set off like it was running on 3 1/2 cylinders, not at all smooth, but did have a tickover, if a raggedy one. I put this down to having no choke, coming back it seemed ok. The second longer journey it ran ok, ticked over at the lights, but after a 20 minute stop heat soak seemed to have got to the setup, and the tickover was dangerously high again, bordering on undrivable. On my return I checked everything I could, there was still slack in the throttle cable, but I did find that the nuts on the carb manifolds weren’t tight, the near side carb you could actually move a little. I expected that tightening them and eliminating an air leak would fix things but it didn’t, though maybe it could explain it running so rough from cold. Current state of play is that I’ve screwed out the throttle stops to get a fast but not insane tickover, but I won’t find out until tomorrow what it’s like cold, if it runs at all. Zed, if it is still up the pictures as I expect, can I take you up on your offer and bring it over sometime next week? I’ll sort it with you by pm if it’s still not right.
I got one of those snail meters. It works fine but is about tuppence worth of grey plastic. And then I found I had to pay an extra £25 for an adapter to fit standard PDSIT 34's. Sod it. I made a prefectly good adapter out of the cap from an aerosol can and some draught proofing strip.
Do you have the thick fibre insulators under the carburettors to deal with heat soak? An air leak could cause idle problems. A carburettor could be jamming slightly open through wear - the throttle plate moves sideways, wears a step in the choke bore and catches on it, or maybe as things warm up a slightly bent spindle might be causing jamming. This can give fast idle.. basically for an engine to idle significantly fast, air has to be being supplied when not needed.. as the air pressure under the throttle plates idling at 850 rpm will be about half atmospheric and it's almost impossible to suck more air through carburettors as simple as ICTs without moving the throttle plate..as theres no additional idle air path which the stock carburettors feature.. Idling badly cold is one of the penalties for not having and using all the stock cold running hardware.
