Setok Posted April 15, 2009 Share Posted April 15, 2009 After last weekend's Weber adjustment act I started off today in almost perfect fashion (the Xflow still has trouble firing up for some reason — fuel evaporation?), except that while approaching the petrol station I noticed the revs were pretty high, around 1200. So bonnet off and adjusted the idle speed down to around 1000. Set off again, but while driving through town I noticed the temperature was getting worryingly high, and the idle speed was up to over 1200 again, then 1400. Luckily it was a short way to work as I was getting quite concerned about that temperature needle approaching the red. Even when moving it never dropped below 90. I let the car cool down for a bit and then took off the bonnet to have one more look. The screw was still where I had adjusted it, but revs were still high. Then I noticed that a touch on the throttle hm 'bit' (the thing the cable is attached to) would lower the revs way down again. This would lead me to believe it's not closing properly, despite the double springs, or is this normal? If not, what do I do about it? I guess that could be one explanation why my idle swings around a bit... --- Kristoffer Lawson Link to comment Share on other sites More sharing options...
jonboylaw Posted April 15, 2009 Share Posted April 15, 2009 Hi Kristofer, I had the exact same problem, it is not the return spring, but the cable adjuster where it goes into the pedal box, just slacken it off slightly so that the throttle completely closes then adjust your idles when the engine is warm... I used to get a 1500 - 2k Rpm at idle when warm!... Jon Link to comment Share on other sites More sharing options...
Molecular--Bob Posted April 15, 2009 Share Posted April 15, 2009 It may also be a sign that the pedal bush is a bit sticky, I had to replace mine as it refused to loosen up after many and various oils were applied. My throttle pedal would stay where you put it when the cable was removed. I also changed the cable and added a second return spring to the linkage, one of these fixed the problem. Link to comment Share on other sites More sharing options...
Setok Posted April 15, 2009 Author Share Posted April 15, 2009 I don't think it's the pedal bush. I wiggled the pedal up and down and it seemed to be moving freely. However I did notice that it wasn't pushing the cable in and up (out of its holder) the way it used to. So while the cable seems to move well enough in normal driving, and looked relatively clean, it might be that it's sticking. I tried WD-40 around, but to little effect (at the same time I tried to check if there was an air leak in the carbs, but didn't notice anything). When I push up the bit that holds the throttle cable the revs drop quite dramatically, even though it feels like it's not moving at all (and indeed only moves by the smallest fraction). --- Kristoffer Lawson Link to comment Share on other sites More sharing options...
Panto Si Posted April 15, 2009 Share Posted April 15, 2009 I had this happen, turned out my return spring wasn't actually connected to the right point, so not enough tension! Double check where the spring(s) are connected. Beaulieu #28 Oi! Saxo boy! you might think it's ugly, but you're only gonna see the back anyway! Link to comment Share on other sites More sharing options...
Bilbo Posted April 15, 2009 Share Posted April 15, 2009 Setok Its worth checking that the two external springs are not hitting each other I have had that problem and it did effect the idle speed. When I pushed the throttle it idled normally. Checking it on my own was a waste of time I only found that the springs were touching each other above ¾ opening by watching them with somebody in the car using the accelerator peddle. After adjusting the angle most of the external springs the problem went away. So I changed the external springs and it was fine after that but it’s a bit of messing about as you do need to get the same tension on both or it happens again Also remove the internal springs with two external springs you do not need them and they could be the problem One other cause is that the butterfly spindle bearing are a tad worn and the butterflys snagging that’s a real pain to sort out in the end Roger king set the spindle up for me Normally mine idles perfectly on 800 rpm or even a tad lower Hope this helps 'Can you hear me running' ......... OH YES and its music to my ears 😬 😬 😬 1988 200 bhp, 146 ft lbs, 1700cc Cosworth BD? engineered by Roger King, on Weber's with Brooklands and Clamshell wings, Freestyle Motorsport suspension. Link to comment Share on other sites More sharing options...
Setok Posted April 15, 2009 Author Share Posted April 15, 2009 OK, a description of my springs... I have a V-shaped spring (whatever they're called) underneath, which pushes upwards. I just noticed there is another hole the bottom end of that which it could be attached to (it's connected to a lower hole). This would result in more tension. That is the original spring that I had when I got the car. The top spring is a normal small spring from a hardware store. It has been changed as the previous one broke. Unfortunately I could never figure out for sure where to connect the bottom end of that spring, as that was what broke off on the original (and I had never previous checked where it was fixed to). The top end is attached to a bar that runs between the two carbs which has a hole probably just for that. When the throttle is closed, this spring is lightly tensioned. Currently the top spring is attached to the bit of the lower spring that sticks through the metal that connects to the carbs' throttle mechanism. Should've taken a picture of this... If anyone can tell me how the top spring should be connected for optimal performance, I'd be much obliged! So yes, they are in contact, but perhaps not in the way you imagine, Bilbo, as they are two very different springs and attached one up, one down (and in this case blipping the throttle didn't bring the revs down ☹️). --- Kristoffer Lawson Link to comment Share on other sites More sharing options...
Molecular--Bob Posted April 15, 2009 Share Posted April 15, 2009 I'll put a picture of mine on webshots tommorrow and point you at it. I can't say that its the right way to do it, but it is how it was on mine when i got it (no spring fitted though). I made a new bracket out of alloy as the original was a bit of rusty old iron, but the shape is the same. I used a spring out of a weber linkage kit that i had in the shed. On mine this is looped around the end of the linkage where it bends through 180 degrees. The spring is always under some tension. Link to comment Share on other sites More sharing options...
millsn Posted April 15, 2009 Share Posted April 15, 2009 Is your throttle cable itself old/worn? does it glide smoothly in and out. If the outer sheath is damaged it can hang somewhat. The other thing to consider is if you still have the original black yoke that hangs from the carbs to hold the carb end of the cable outer. This can get loose and wobble giving all kinds of strangeness. If so, bolts need removing, degreasing and putting back in on loctite Link to comment Share on other sites More sharing options...
Setok Posted April 16, 2009 Author Share Posted April 16, 2009 The cable itself is at least a few years old (I've never changed it). At the pedal it feels like it's moving smoothly, but I'll need to release the carb side of it to properly test. Yes, I still have the black yoke. Good point. I'll check that is OK. --- Kristoffer Lawson Link to comment Share on other sites More sharing options...
jonboylaw Posted April 16, 2009 Share Posted April 16, 2009 Kristoffer, Did you try slackening off the cable where it enters the pedal box ? Just a couple of turns should tell you if it is that. Jon Link to comment Share on other sites More sharing options...
Setok Posted April 16, 2009 Author Share Posted April 16, 2009 jonboylaw, I haven't tried that yet. I was thinking about it last night, though. I mean in the sense that shouldn't you actually be 'tightening' the bolts to loosen the cable? That means putting less curve on the cable which means less distance to travel and thus more "poke" upwards from the bet on the end. But yeah, I'll be looking at this over the weekend. --- Kristoffer Lawson Link to comment Share on other sites More sharing options...
jonboylaw Posted April 16, 2009 Share Posted April 16, 2009 Actually, just tighten one and loosen the other so the outer cable is free to more and then you should get a nice tick over.... once you have made your adjustments, just adjust the nuts to lock the cable in the right position, a bit of adjustment should have it working fine, assuming this is the problem. In my case the engine would tick over nice when cold, but once warm and sitting at the lights, tick over would be around 1500 - 2K rpm, I often had to put my toe under the throttle pedal and pull it towards me. I was considering stronger return springs or even a new linkage but my brother suggested slackening off the nuts and hey presto, the revs dropped right down to 900 rpm. Jon Link to comment Share on other sites More sharing options...
Bilbo Posted April 16, 2009 Share Posted April 16, 2009 Setok Both of my springs are the same here and sit side by side attached to the standard Caterham Y bracket hence the two holes Basically the standard Caterham set up 'Can you hear me running' ......... OH YES and its music to my ears 😬 😬 😬 1988 200 bhp, 146 ft lbs, 1700cc Cosworth BD? engineered by Roger King, on Weber's with Brooklands and Clamshell wings, Freestyle Motorsport suspension. Edited by - Bilbo on 16 Apr 2009 19:02:46 Link to comment Share on other sites More sharing options...
Setok Posted April 16, 2009 Author Share Posted April 16, 2009 Bilbo, that's what I have underneath. The top spring is a normal small spring which connects to the top end of that throttle return spring and pulls upwards and inwards (a bit). --- Kristoffer Lawson Link to comment Share on other sites More sharing options...
Bilbo Posted April 16, 2009 Share Posted April 16, 2009 Kristoffer Well as stated I have two of thoese so you setups non standard but that does not mean it should not work but it is better if the springs have the same tension one for each carb as I do 'Can you hear me running' ......... OH YES and its music to my ears 😬 😬 😬 1988 200 bhp, 146 ft lbs, 1700cc Cosworth BD? engineered by Roger King, on Weber's with Brooklands and Clamshell wings, Freestyle Motorsport suspension. Link to comment Share on other sites More sharing options...
Setok Posted May 1, 2009 Author Share Posted May 1, 2009 I actually have another standard return spring so, in theory, I could at some point configure the standard setup with two springs. I've been playing around with some help from people here and this could have been two things: surprisingly enough I have two idle speed screws, one for each carb. I only realised that when Vinnie over here was adjusting a different screw than me. Then we realised both were connected. Obviously that could interfere with the whole balance mechanism. The solution was to screw out the other one enough to make it not have an impact. The other thing was that my throttle cable, which has perfect movement, was attached by a tywrap to the side. This was deemed a bad idea and could actually be the reason behind everything. It's not difficult to imagine the throttle cable tightening causing itself to rub against that tywrap, with resulting friction inside. That has now been removed. I can still push on the balance screw, and the throttle mechanism, and even with a small touch (like when screwing the balance screw) the revs will drop. Could someone perhaps test to see if their Weber mechanism does the same? --- Kristoffer Lawson Link to comment Share on other sites More sharing options...
Normans_Ghost Posted May 2, 2009 Share Posted May 2, 2009 I ditch the Weber springs as I've had them break and throttles stuck wide open on more than one occasion. I use Mini type SU prings affixed to a small bracket held in place by the top cover screws. One on each throttle arm is good. Norman Verona, 1989 BDR 220bhp, Reg: B16BDR, Mem No 2166, the full story here You and your seven toThe French Blatting Company Limited Link to comment Share on other sites More sharing options...
Bilbo Posted May 2, 2009 Share Posted May 2, 2009 Setok Have a look at where the balance screw hits the arm/stop in the past the arm on mine became pitted from use so Roger King fixed an old valve shim to the arm much harder no more problems. In my case it just made it hard to balance the carbs. What was happening was the idle screw was hitting the edge of the err hole/dent then slipping in as you used the throttle and did have an effect the idle speed. 'Can you hear me running' ......... OH YES and its music to my ears 😬 😬 😬 1988 200 bhp, 146 ft lbs, 1700cc Cosworth BD? engineered by Roger King, on Weber's with Brooklands and Clamshell wings, Freestyle Motorsport suspension. Edited by - Bilbo on 3 May 2009 13:33:06 Link to comment Share on other sites More sharing options...
Setok Posted May 3, 2009 Author Share Posted May 3, 2009 Bilbo, now that is an interesting point. I wouldn't be surprised if there was something funny there... --- Kristoffer Lawson Link to comment Share on other sites More sharing options...
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