Following from the other post Pete. Took out the idle screw and put back in as said bout 7mm left at top of the tube. Plugged the hole with a circle of rubber (I presume its the same as having the rubber grommet fitted) Started up, idle was terrible then revs came back up to around 1800 (rev counter fitted now BTW) Had a feel around the HT leads etc and the dizzy feels a bit loose ie; I can turn it 10' each way, either way causes real bad idle which i'm guessing knocks out the timing. found the smoothest idle position for it and left it there (which also increased the idle to bout 2k). Did all the other checks on the FAQ, the 3-4PU does work fine and when I unscrew the 13mm nut for the idle, the plunger does retract a few MM (which would lower the revs.........if the lever and the little screw were following it) but it wasnt touching the plunger at this point. Was the same during warm up from 4'C to hot engine sucking in 24'C air. Engine off, carb off, carb in living room..... Expansion element off (easier than I thought) element plunger sitting 3mm proud of the housing. into hot water slowly came out to sit proud about 10mm. into ice cold water , doesn't retract but can be manually pushed back to sit 1mm proud of the housing. done this a few times to get some quick movement for it. The mechanism that the expansion element pushes seems quite free moving. next steps/checks whilst carb's off? EDIT: all the vac pipes are good.
Easy to get at and check the part-throttle heater now, as per post #39, if you haven't already. Waxstat sounds like it may be OK, 1mm is just within tolerance. It shouldn't go back in by itself after heating/cooling, as it takes the force of the return spring to do this when it's fitted. So that's fine. What happens if you apply gentle-moderate pressure when it's in its hot, 10mm-out state? I haven't tried this myself, but would assume that it should not push back in much if at all, as it would normally be pushing against the return spring when installed. Dizzy loose? That doesn't sound good. You don't mean just the cap? That can usually be moved a bit within the grasp of the spring clips. Timing strobe-gun treatment advised to get the ignition timing bang on. That may be very relevant to all these troubles. Replacing all the vac hoses is so much easier when the carb's on the kitchen table, so I assume you'll do that. Try to keep them all about the same length as originally, or you'll find that they're banging into the firewall round the back if you make them longer. Check all vac nipples for gunge as you do the hoses, and give the butterflies and nearby areas a nice clean with carb cleaner. Unrelated to your current probs, but you may as well check that the secondary throttle works while you're at it. Suck on a length of vac hose attached to the secondary vac unit (the round black thing with one hose, at a jaunty angle N/S/R of carb) while holding the primary throttle wide open with the main spindle. It should open the secondary throttle and hold vacuum to keep it open if you block the hose while it's fully 'sucked'. I'll probably think of more, but that'll do for starters.
part throttle heater seems fine, and gets 12V. will test the OHMs after. Yeah the waxstat sits no less than 1mm at cold and out of boiling water can be pushed in to a point of leaving 10mm proud. .ps. the waxstat plunger came out, nothing else came out. pushed it back in and it works exactly the same. Doesn't look like anything has broken off it. Dizzy, all of it! Cap is solid won't really budge. The whole thing could be moved round, it's not so loose that you can rock it, and does stay put. Can this be tightened? All vacuum pipes are good, all hold vacuum with my tongue on them IYKWIM. Secondary butter fly works spot on. and hold with vacuum. let me try to explain something.... With the waxstat removed and with the little screw on the lever (3-4PU side) half way through it, the little screw just touches the 3-4PU plunger, which is extended to 14mm. Is this okay?
There's a M8/13mm hex-head bolt just in front of the dizzy that should clamp it against rotation when done up. Do test the Ohms of the heater when it's on the carb, 12V will do it no good if it has no earth path. Do the same test on the autochoke heater, should be about 12-13 Ohms from feed-wire to carb body (not just to the outer metal water housing, I'll explain why after my tea with a piccy of the earth link that often gets bust). I'll have to put a 3-point unit back onto one of my spare carbs to try to answer your last question, they're all fairly stripped-down at the moment.
Also before it's back on the engine... Should the primary throttle butterfly be totally sealed closed when nothing is pulling on it? I haven't touched it but I'm unsure if it's set right, Because there's a tiny 0.5 - 0.75mm gap each side when it's snapped shut.
No, it is being held open by the 3-point unit plunger pushing on that screw. Probably should be a touch more than that 0.5 - 0.75mm, which might explain the struggle to idle at first start-up. I'll get a 3PU on a carb now-ish, and see. If you put it back on the engine before I get back to you, do be careful to get the throttle-cable back on just right with necessary slack on the inner, or you'll be revving for Britain...
Okay, I see now (primary throttle butterfly) I've moved the screw in a touch and the butterfly is around 1mm open. I think the problem's the waxstat. Looking down the side of the carb from the autochoke side you can see the spring and mechanism the waxsat pushes onto. Once I fitted waxstat back onto the carb, the square steel rod it pushes extrudes by 0.5mm, cold. Dunked the waxstat into BOILING water and left for a few minutes, still fitted to carb, and the steel rod it pushes came out to 5 - 6MM. Is this enough?
On all 4 stripped-down carbs I've just looked at, the screw is sticking out more on the 3-point unit side of the plate than the other side, maybe 7-8mm of thread showing on the 3PU-side and 3-4mm on the free side. On the one I've just put a 3PU back onto, the primary throttle is certainly more like 0.75 - 1mm open, rather than 0.5 - 0.75mm, so maybe that screw has to be wound through some more towards the plunger. (If the fully warmed-up idle is then too high, you can correct it with the 13mm nut on the back of the 3PU).
Maybe not. When the waxstat is fully hot, it should cause the cam to rotate far enough clockwise that the round stop on throttle mechanism that rests on it during warm-up should drop off the LH end of the cam, allowing the throttle to be controlled completely by the stuff on t'other side (3PU).
DO you mean the little stunt peg like stop? If so, It's not resting on it. And makes no difference when I fully open the mechanism.
FWIW, this is the metal grounding 'washer' on the autochoke that connects the metal water housing (and ground-side of electrical heater) through one of the screws, to the main carb body. All the spare carbs I've seen, and the one on my car have this washer broken just the same as this one, where the green arrow is pointing. This makes the heater useless, even if it's getting its 12V correctly. Note: that pic is a 2e3 part, but it's the same arrangement on the 2e2.
Will only affect the first couple of minutes of running, making the choke-flap open slower than it should, resulting in an over-rich mixture. Fairly easy to solve by adding an earth lead that contacts the metal water housing and goes to a good earth somewhere.
Also, whilst the 3PU was off. I connected up the waxstat hose to my taps (boiling water) Same thing, steel rod comes out 5mm or so, it does let the 'stop' come off the cam, not totally, but if I open the mechanism more it makes no difference to the throttle, and the throttle doesn't move any further.
[Reply to post #57] Yep, that'll do. You'll almost certainly have to clean off some muck and corrosion to get good contacts, but that should do it.
Also, whilst the 3PU was off. I connected up the waxstat hose to my taps (boiling water) Same thing, steel rod comes out 5mm or so, it does let the 'stop' come off the cam, not totally, but if I open the mechanism more it makes no difference to the throttle's stop, and the throttle doesn't move any further. Going to refit in a mo.
