Lotus waist trim

My car has two styles of waist trim- there is a plain square trim fitted to the nose and a stepped profile attached to the doors and around the boot. The parts list gives two styles of trim- a stepped profile being the earliest so I am assuming that at some point the nose trim has been replaced on this car using the later style. There is some damage to the nose trim which I have infilled with acetoxy silicone black rtv sealant- this actually gives a reasonably smooth repair and it will do until later.

Nose trim infill- maybe a little more needed but much better than a gaping hole!

Stepped trim to rear of car

Older style ridged trim fitted to rear of car from doors backwards.


Newer style square trim fitted around nose of car- doors forwards.

The trim is missing completely from the driver's door but the mounting strip is in position. The mount is cut a little too short I think, as it would leave the ends of the trim unsupported. Perhaps another explanation for the early departure of this trim. The ends of the rail are cut and chamfered so I dont think its broken, I think it was just fitted that way!

Drivers door- trim strip missing but mounting rail is in position. Note that it ends short of the door edge by some distance!

Since this car is already a montage of styles- and since it will all need to be replaced with the correct style if/when I get it resprayed, I thought it wasn't worth investing in the correct trim just for this door. This sort of material must be very common and I think owes a lot to Mr Chapman's interest in GRP boat construction. I therefore sourced some from alternative (non-Lotus) suppliers and found 0.85mm square style trim at  £3.35 per meter. (U Channel Edge Trim 8.5mm x 8mm TMH8SQ Edgetrims.co.uk). Its pretty much the same as the later style trim but not a perfect match. Its is thinner than the real trim and doesnt require heating to soften it before application. This I think is a good thing since it should mean that it won't shrink quite so much after application.

The waistline  trim is held on with polyurethane adhesive Puroflex 40 (PU40) widely used as a sealant and glue in the caravan industry and widely available around £4 a tube. I got mine OTC from Toolshack.

There is no trace of adhesive on the door trim mounting strip- which either means adhesive isnt really needed for the correct trim... or more likely explains why there is no trim on this door!

Fitting trim by hand (cold) to determine length

I pushed it on by hand so I could cut it to a generous length. I then applied a bead of sealant along the trim strip.

bead of sealant/adhesive along outside and top of the mounting rail.

I put the glue on the mounting strip: the SJS guide below suggests putting it on the trim; I'm not sure which would be best.
I also filled in the ends of the trim strip where it will project past the mounting strip. It might not work, but I'm hoping it will stick to the doorskin here and won't need to be cut off quite as short as the mounting strip. In any event when I trim it to length after 24 hrs the ends should give a nice solid texture.


The trim is then applied again by pushing it into the sealant and then smoothing it down with a wallpaper roller.

 This causes the sealant to bulge out a bit- I probably used too much, but it seems a good idea to fill in the gap between trim and door skin.

Trim rollered on- some sealant has squeezed out.

Ends left projecting- I will cut to length when the trim has had a chance to shrink if its going to do so.

The excess sealant can be wiped off with white spirit leaving the trim to set onto the door. I will leave it for 24 hrs and then cut the ends at a chamfered angle- hopefully further towards the edges of the door, but if this region is still unsupported I may have to cut closer to the ends of the underlying mounting strip.

Door strip applied- left to set overnight before trimming.

... Eventually I had to revisit this and unify the trim style around the car as well as replacing the trim around the nose. You will find this described here.

Hints & tips... taken from SJSportscars website....


Instructions for waistline fitting. Remove the old trim. This should be simply a matter of pulling. Be a little careful, sometimes it is possible some repaired sections might come away with the trim. Paint can also come off, if it was done poorly last time. Clean off the remains of any old adhesive. In the case of the door sections, make sure the carrier strips are secure and in one piece. These are often held to the doors with small self tapping screws which can go rusty creating a lump in the trim. You should consider replacing these with the currently recommended countersunk pop-rivets, SJ075W0011. Sand the vertical face of the body lip with course sand paper. The new trim is made soft and workable with a heat-gun. It will melt or burn, if you get it too hot. Put a section on the car and then gently shape and push on to the lip. Secure with lots of strips of masking tape. Do not pull these too tight, they can cause dents in the finished trim. You need to use a lot of the strips of tape. Do not stretch the trim as you apply it. Over the years that it will last, it will shrink, it will also shrink a little as it cools, so do not stretch it now. On the Esprit S1 & 2 the front wing section needs to be trimmed in thickness so it sits flatter against the body as it goes under the front bumper. Do not attempt to join any section of trim, it will not work! When you have the complete car covered, and the ends trimmed, slightly too long, leave the car overnight to cool. Gently take the trim off and you will find it will stay in the correct shape. With a small piece of left-over trim, gauge how much of the Polyurethane adhesive SJ075B0007 to put into the groove of the trim. This will vary as the size and depth of the lip does change. You need enough to touch the flat face of the body which you sanded earlier but not so much as it comes out. Apply adhesive in the groove of each section of trim and attach to the car. Check as you go, that the glue is making contact to the flat face of the body as planned. Hold each piece in place on the car with lots of tape as before. When you are happy, leave over-night to set. Remove all the tape and trim the ends at the required angle. Theses are around 30 degrees, except for the front of the doors, which need around 60 degrees. Fill the open holes in the ends with more adhesive and smooth off. Steve Roberts

Lotus Excel DHLA45 carburettor and manifold rebuild; refitting inlet manifold

I bought the Dellorto rebuild kit from Eurocarb- kit containing 170 size needle/ valve. Their service was amazing with delivery within 24 hrs. The kit itself was a little disappointing- mainly because it didn't include the needle valve filter or the Dowty washer for the fuel union. The latter is probably forgivable as this seems to be peculiar to Lotus, but the valve filter must be a Dellorto part. Also, I felt that the   fibre washers were a little flimsy and insubstantial compared to those already fitted and 2 of the gaskets had been changed to paper rather than the black nitrile-like stuff that was present originally. None-the-less it contained the most important parts needed- plus I think a few more and this did raise a little confusion.

The contents of the kit (one carb's worth) are shown below sorted out to put the similar parts together.

Contents of Dellorto DHLA45 rebuild kit (1 carb- kit actually contains parts for 2)

I have tried to list what goes where (as I see it): Top left are the fibre washers and filter for the banjo union- not needed in the Excel, then come the 3 carburettor body gaskets (fitting obvious) and a variety of washers. 

There are 2x 12mm fibre washers (base of Acceleration pump jet). 1x 12.9 mm Aluminium washer (base of needle valve filter holder); 3x 8mm (1.75 mm section) nitrile O rings (2 for the idle jets and 1 for the pump non return valve); 1x 8mm (1.75mm section) nitrile O ring (not needed?); 2x 6 mm (1.75mm section) nitrile O rings (top of acceleration pump jets); 2x 5.4 mm (1.5mm section) nitrile O rings (Idle mixture screws? or not needed).

Then there is a replacement diaphragm and spring for the acceleration pump, a new (170) needle valve unit (in plastic box) and a new pump arm return spring.

As I said above the Dowty washer for the fuel inlet was not included. This presented a bit of a problem as its not immediately apparent what size is needed. The union (shown below) is threaded at 20 tpi on both sides. However one side is 0.5 inch diameter and the other 0.47inch. I think the 0.5 section (i.e the side that screws into the carb body) is actually an M12 fine, but I can't identify the other side which is as close as I can see a BSC fitting! However the Dowty fits on the 0.5 inch side so an M12 (or probably also a 1/4 BSP) bonded washer should fit. I have ordered a few- they are very cheap and for £69 could perhaps have been included in the kit!

Fuel union fitting- Bonded washer on 0.5 inch thread.

I finished sonicating and cleaning all the components of the first carb and sorted them for assembly. All components are screwed in tight except the mixture screws which I haven't removed. I did check that both are clear and I will adjust them on the car... if and when I get it running!  I don't want to remove the anti tamper plugs until I am ready to do this- I have got new ones also from Eurocarb.

A few other points... the acceleration jet has a flat on one side... if you look carefully there is a matching flat in its socket which means it will only fit one way round... with the outlet hole pointing towards the motor.

Flat on acceleration jet 

Matching flat visible inside acceleration jet mounting hole (lower centre) on the right of the hole... zoom in for clarity.

To fit the acceleration pump mount the spring on the diaphragm centre boss. Line it up on the pump top and lower into position.

The throttle needs to be held open to allow the acceleration pump to descend in a flat even manner across the carb so the diaphragm can be aligned and the screws can be tightened.

Float chamber cover gasket must be fitted before the float- don't forget to insert the needle into the float before fitting! I fitted the original needle valve filter to the new valve seat as there was no replacement included in the kit.

As before fit the float pin from the solid support side tapping it towards the split support. Once fitted, I checked the float height to the gasket measured at the base of the float (narrowest point)- the gap was 12mm|* as specified. I also checked the droop distance and this was as specified 27mm as well. Overall no adjustment needed on this carb.

Setting float height 15mm at lowest point of float to gasket surface.

* Ah well- it pays to read and remember the book better! This should have been 15mm by Mr Hamill's reckoning, so I was setting the float too close to the carb top- ie too high; and it will permit too high a fuel level if set like this- I had a lot of overflow/fuel drip problems later on when I finally got the motor to run.  I will post an entry with more about about float heights  and fuel levels later on- if I ever solve the problem that is!

The rest of the rebuild really went as expected so I'm not going to present any pics- safe to say the first carb is complete- I have one more to do and the moment of truth approaches!

I then rebuilt the second carb before fitting them both onto the inlet manifold. Although I do have one already prepared, this has a different layout for the coolant connections so I will refit the original manifold.

The old manifold needed to have the spacer mountings removed. 

spacer in position- flattened O ring on top...

... and beneath

Removed spacers before cleaning

These were quite tight but tapped out and I cleaned the spacers in the sonicator and polished the conical recess sections. The point of the cone goes towards the motor and helps to prevent reversion of gases from the manifold into the carburettor.

Cleaned units- new O rings for the spacers were included with the head gasket set.

Clean up manifold surface then assemble ring to the conical side and insert cone side down for anti-reversion effect.

spacers fitted

I then inserted a second o ring into the top of the spacers before aligning the carbs at the slip link and offering the pair up to the manifold- they slipped on easily.

Refurbed carbs in position on inlet manifold.

Slip linkage

 The carbs are bolted down using the spacer rubber washer/cap washer system The cap washer goes on first but those fitting to the lower studs has a flat facet to fit under the bulge of the carb.

flat facet (top) on lower cup washers.

 The rubber washers then slip on followed by the second cup washer and finally the captive nut. I tightened these down evenly trying to get an even 1mm gap around the carb and spacer and between spacer and manifold. The idea here is not to tighten the carbs down firmly since this would ruin the shock-absorbing function of the spacers.

Tightening the carbs- I used a strip of aluminium 0.9mm to judge the gap. Its necessary to alternate between top and bottom gaps until both are right.- Use 2 hands- I have to use one to hold the camera!

Carbs installed

Manifold and carbs from above: Much cleaner!

Once the carbs were on the manifold I checked that the throttles opened evenly. To do this I removed the progression hole covers and placed a lamp behind the manifold blocking off direct light. I could then fix the throttles in a set position with a screwdriver and check that the progression holes were evenly exposed.

Throttles jammed with screwdriver and inspection light positioned above manifold openings.

 I could then look through the progression holes from barrels 2 and 3 to judge the position of the butterfly. The linkage screw can then be tweaked to set them at the same point. Finally the screwdriver was removed and I checked for even sweep of the butterflies across the holes as the throttle was moved. Only a small adjustment was necessary.

butterfly position revealed by light through the progression holes

Butterflies slightly out but corrected via linkage screw.

I could then fit the manifold to the motor- new gasket of course. In fact the last remaining gasket from my top and bottom end sets!! Very satisfyfing to use it! I cut the manifold to pump water hose to length carefully so that it would fit well onto the water pump and manifold. I fitted it to the pump first using marine protection grease to make sure it slipped on easily.

 Loading the jubilee clips onto the hose and then insert the manifold by sliding it into the hose and pushing it back onto the studs.

The clips can then be tightened- access not great but possible. The rearmost clip could be reached through the gap between the manifold throats.

water pump screw- access no problem!
There are earthing connections from manifold to thermostat cover and from rear card to manifold nut. I connected the choke cable and link using the nut I had made to replace the missing fitting and fitted the throttle cable.

Finally I reattached the belt guard and clipped the throttle cable into the guide on the guard.

I still need to insert the plugs but I want to spin the motor a bit first to spread oil; I filled the motor with 6l 20/50 mineral oil and added water to the reservoir allowing it to sink down. I added PAS fluid to the pump reservoir and jacked up the front of the car to turn from lock to lock to spread it before topping it up again. Finally I could spin the motor on the starter and then top up the water and PAS fluid again

I had anticipated getting detectable oil pressure just by spinning the motor, but since this was completely dry, I think this might not be possible straight away. The motor is now pretty much complete and back in- sadly at the moment although it looks really good its pretty much an ornament until I can try to start it and I'd like to find some way of checking that the oil is being circulated before I do that.

DHLA 45 Carburettor strip

The DHLA45 is probably the pinnacle of carburettor development: the last flowering of that black art before carbs were pretty much universally abandoned for injection systems. As such these are devilishly complex carburettors! I do know why this car was laid up- and it wasn't due to carburettor failure. This of course doesn't mean that the carbs haven't been messed about in the intervening years or simply become gummed up with crystalline deposits from long vanished fuel. Anyway I had intended to leave them well alone but sadly this proved not to be possible. Firstly the nuts on one carb were only hand tight- I therefore detect the malevolent lurking presence of the LBPO- and there is no telling what he might have done! Secondly, the carbs had been left exposed to the air with no airbox and the bonnet open for some time before I got the car. There is a lot of grit and general muck blown into them. It doesn't look like I can avoid a clean, strip and rebuild but hey- its all a learning curve! Luckily I found  Des Hammill's excellent book on Dellorto and Weber carburettors  which is an excellent guide and has increased my confidence to the point where I just feel able to tackle something!

The first problem was getting the carbs off the manifold. I gave the lot a good clean with paraffin and then carb cleaner and set about removing the carbs- each is mounted to the manifold by 4 bolts which pass through MISAB double rubber washers sandwiched between cup washers. The anti-vibration mounting for the carbs to the inlet manifold is completed by rubber mounted  metal rings also made by MISAB in Sweden.

Carb mounting bolt- shock absorbing mounts consist of: cup washer/double rubber washer/cup washer

The carbs are linked so that their throttles operate together. This is achieved via a peculiar sliding link so that they can be disconnected without affecting the setting. However they can't slide apart until they've been moved forwards and off the studs. What this means is that its not possible to remove just one carb- you have to dismount the pair and then split them. No real problem as I do need to clean both- but I will dismantle them one at a time!

Sliding mount joint between the throttle levers.

Sliding mount from 90 degrees- note the spring loaded adjuster screw pressing down on the spring loaded pad. Between then is the link lever from the next carb.

Removing the carbs and separating the slip link

Sliding joint separated-note tab on throttle lever lhs carb that slips between the two spring loaded screws on the rhs carb.

This is the cleaned carb that the LBPO had been messing with.

I unscrewed the two screws holding the top plate on to expose and remove  the gasket beneath.

Gasket below top cover

Removed to expose jets

This exposed the two main jet/emulsifier tubes (larger) and pilot jets and emulsifiers (smaller). These 4 jets simply unscrew- the pilot jet being a little stiffer as it has an O ring on it. Both types of jet are composite units and just pull apart.

Main jet emulsifier unit

 There was some trace of dirt on the jets but I've seen worse...

slight amount of dirt on main jet

Removing the pilot jet

7

Slightly more dirt on these.

Surprisingly the remaining screws in the carb were all very tight- which suggests the LBPO gave up fairly early in his bodging mission of destruction. I loosened them with an offset screwdriver.

Loosening the cover screw on the progression holes

Exposing the progression holes also found a little more sediment- there was a surprisingly large number of these holes; I was only expecting 4! The black plugs above the progression holes are the blanking plugs that keep grit out of the mixture screw threads.

The next step was to remove the venturi and choke tubes which sit in the carb throat. The venturi is farthest from the throttle butterfly- in my case it was a bit dirty. 

Venturi- some obvious dirt in there and some sticky gum cementing them in. This is the airbox side of the carb and i had expected 4 studs per carb for attachment. Strangely I have only 2 and the vacant hole is visible here. This hole hasn't even been tapped so I dont think I have a stud missing. Maybe a nut and bolt?

Venturi looking through the venturi and choke tube towards throttle butterfly, single support for the central venturi.

The venturi is held in with a stud and lock nut on the side of the carb- I removed these.

Venturi locknut visible below acceleration pump.

The venturi and choke are both tight fits in the carb body. To remove the venturi you need to warm the carb to loosen this grip and then tap the venturi out away from the butterfly using a wooden drift inserted through the butterfly which is opened to allow this. I used a dowel drift on the supporting arm visible in the venturi illustrated above. A few taps saw the dowel split but the venturi shifted

Dowel through the butterfly and onto the venturi support strut- hold the carb and tap firmly with the hammer.

Venturi emerging

 Given that the venturi was tight I had expected the choke to be tighter- apparently it can be a real pig. Luckily the choke just fell out once the venturi was free.

Choke dropped out with the venturi

Venturi is rough and pitted- will need smoothing before refitting.

The other side behaved in the same way. I stored them separately, marked as to which side of the carb they had come from. I'm not sure this is essential but seemed a sensible precaution.
I then removed the acceleration jet (brass screw located behind the progression hole cover).

Removing the acceleration jet.

The jet and cover screw are linked and do not obviously separate for cleaning. They are probably just a firm pull but I don't want to break anything.The lower part is loose in the upper so I did the best I could to make sure that the holes were clear and carb cleaner squirted through.

Cover screw with acceleration jet inserted

I removed the top cover by unscrewing the 4 screws; 1 of which bears the ID tag for the carb.

removing the top cover

I could then tap the cover loose and lift it upwards- note it has to go up vertically a couple of mm to clear the choke tower

Raising the top cover- choke tower has to clear the cylindrical projection below- this can be tight and needed a tap to free it in my case.

Float chamber cover removed

As the top was lifted the floats became visible beneath. These have to be removed to swap the gasket below

Floats hanging beneath chamber cover, note black gasket above floats- can't be changed without removing the floats.

To remove the floats you need to tap out the pin but from the solid support side- towards and through the split support. Reinstall the same way as to tap on the split support risks breaking it!

Using a small pin punch to tap out the float pin

 Once the pin was out the floats came away with the needle valve inserted between the forks as shown here.

Needle valve fixed to float hinge

 I set the float aside and then returned to the float chamber cover. This is shown below; the fuel inlet is at the top (large brass nut) which then discharges vertically through the smaller brass needle valve fitting which includes an integral filter. This system seems to differ from those shown in the Hammill book where fuel intakes are banjo unions with a large filter inside the cover- I had no such filter. I removed the gasket from the detached chamber top

Peeling the gasket back from the underside of the float chamber cover. Fuel inlet at top centre- fuel outlet to float chamber (needle valve body)  is the brass fitting below

Detached float chamber cover from above-choke tower centre and fuel inlet beneath my thumb.

The fuel inlet simply unscrews from the cover- there is a bonded washer (Dowty washer) beneath but no filter inside in my case!

unscrewing the fuel inlet

The fuel outlet/needle valve body also unscrews from the cover and this does have a small filter inserted in one end. It was fairly dirty but not by any means clogged.

Removing the fuel to float chamber outlet from the cover

The filter itself was in good condition- which is just as well as the rebuild kits from Eurocarb contain only the larger banjo type filter.

Filter in needle valve body- aluminium washer beneath.

  I could then turn my attention to the float chamber; This contained a fairly significant amount of dirt which I flushed out and blasted through all the openings with carb cleaner.

Muck in the float chamber

The float chamber has three brass screws at its end, these consist of the choke emulsifier tube and the acceleration pump metering weights under their covers on either side of it. Outside the float chamber and adjacent to the two progression hole covers is another pair of slotted brass screws which are called the vacuum blanking screws. I have no idea what these do but I suspect they simply close off a moulding or machining channel that is not needed.

Choke tower (top) Choke emulsifier tube (brass centre) and the two acceleration pump metering weights (under the screws each side of the choke emulsifier). Vacuum blanking screws above the metering covers outside the chamber and beside the progression hole caovering screws.

 The choke emulsifier just unscrews and could be cleaned with the carb cleaner

The metering system screw covers were removed and the weight and ball removed- the balls were gummed in the bottom of the bore and so this probably needed doing!

Turning the carb upside down caused the long weight to drop out but the balls needed to be freed with spray cleaner.

Acceleration pump metering system- ball bearing, bar weight and cover screw. The ball goes at the bottom of the bore with the weight on top.

 I then removed the two external vacuum blanking brass screws

... and this completed the strip down of that side of the carb.

Top of carb-stripped!

I could then turn the carb over and dismantle the main well cover. This is in two parts- the centre part is the acceleration pump and this needs to be removed first- 4 screws only. 

Unscrewing the acceleration pump 4 screws

The pump is operated by a spring loaded lever- the length of this seems critical and I was warned not to touch it so I just folded the cover out of the way once it was released.

Cover folds back to reveal pump diaphragm.Some muck on the pump cover and rather more on the diaphragm.

I could peel the diaphragm back releasing its spring.- again a little more muck underneath the diaphragm. Once again I cleaned this out and blasted though the various bore holes with carb cleaner.
 ... peel back the pump diaphragm...

Pump diaphragm removed

 I could then unscrew the outer 4 screws retaining the bottom well cover and ...

Unscrew the 4 bottom well cover screws

... and pull off the bottom well cover and its internal gasket

 ... a lot of muck inside the cover- this is the lowest part of the carb and I guess is intended to collect this sediment. It will also collect any water in the fuel so there are also signs of corrosion here which I will rub smooth before refitting.

Sediment in bottom well-cover- this was washed off with carb cleaner.

The large brass fitting in the well cover is the acceleration pump non-return valve- a hollow brass tube with a captive ball bearing. This was unscrewed and cleaned thoroughly with carb cleaner.

Acceleration pump non return valve

I would usually immerse the carb in sonication fluid- this isn't recommended in the book mainly because it might dislodge more muck into the passages. However I haven't found that to be a real problem with other carbs I have cleaned. None the less there is still a problem with this approach, as unlike other carbs I have worked on, this one contains 4 ball- bearing races. High temperature sonication would probably remove all grease from these bearings! I would change them as they aren't that expensive but they cannot be changed without removing the butterflies and spindles- and this is a major job since any misalignment on refit could make the carbs useless. Accordingly I have no intention of doing this.

As a compromise I immersed the carb but only to a level below the bearings. for sonication. I brushed the top section to clean it. I will remove the oil seals, clean and regrease the bearings (without removing them) when I rebuild the carbs.

Cleaning the carb bodies. Bearing clear of water.

I will work my way through cleaning the other components and finally blast them through with compressed air. In the meantime I have ordered a rebuild kit (170 needle size) from Eurocarb.

There are only two parts I haven't actually removed. The first are the mixture adjusting screws in their turrets and covered with tamper proof plugs. To be frank I'm not sure how to remove these (drill and tap then pull the screw?) but I have checked that the screws aren't blocked and are open to gas movement by squirting carb cleaner through. I have ordered some new plugs so I may return to this point later. 

The second part is the choke system. Hammill isn't very helpful with this part as he states it hardly ever goes wrong and so doesn't describe it- however its probably not a good idea to immerse this either so I cleaned it as before, without submerging the choke tower, and cleaned everything through with penetrating oil afterwards to remove any water. that might have got in.

To be frank- although I found a lot of muck, I have seen worse (!) and I doubt that this level of contamination would have stopped the carbs from working completely. However they might have been unreliable and so overall this is probably a job that needed doing. Sadly stripping, cleaning and rebuilding is relatively easy- its the multitude of adjustments needed as a consequence that might defeat me! The second carb will be treated as the first and rebuilding is expected to be (as they say) a reversal of disassembly! I will post another blog on that as a record.

NOTE

top of carb 2 to orient the tag and cable guide fittings

cable guide indicated.

I hadn't expected to be adding anything more to this particular blog but (as might have been predicted), carb 2 turned out to be rather worse than carb 1. There was a lot more dirt on the needle valve filter and sticky deposits throughout.

gummed up valve

Removing the Venturis was particularly hard with the wooden drifts splitting rather than shifting them- even after warming! I found that a polypropylene rod drift worked much better, didn't mark the Venturi but allowed me to exert enough force that they finally gave up. The chokes fell out as before which was a pleasant surprise- I had expected problems.

Muck in Venturis

One acceleration pump metering ball was stuck immovably in its hole and had to be physically dislodged, the acceleration pump non return valve was also stuck fast.

Non return valve

The acceleration pump jets were also stuck and didn't move freely in their cap screw/holder although they weren't blocked. There was a lot more dirt, and possibly even corrosion on the main jet assemblies.

Corrosion and dirt on main jet.

Nothing appeared to be blocked though.  I cleaned everything up in the sonicator as before and checked that all the channels were open. In this case- given the levels of dirt, I did remove the tamper plugs and check the air control screws were clear- in act they were fine but it was worth checking. In my case both screws need to be bottomed out in their threads and then screwed back 2 3/4 turns.

sediment inside bottom well.

Cleaning the carbs was started partially as a displacement activity because I am more than a little concerned about what might happen when I try to start the wretched thing- but if it was a displacement activity then it is one that has proved valuable. This was clearly a job that needed doing and so I feel vindicated in tackling it before attempting to restart the motor.