OK, I have made some progress in resurrecting my LD1 SOM. The fuel solenoid, Decompression solenoid and their associated linkages had been removed from this unit. Luckily, the bracket that supports all these was still there.

I have now fabricated the linkages from drawings and photos I took of an original unit and I am about to start fitting up an ex-aircraft 24v DC solenoid for the fuel control. This solenoid appears to be rated for continuous service and it will hold in on 12v but I don’t think it will pull in under load at that voltage. The LD1 SOM starting system is only 12v.

To overcome that, I am building a small circuit board that, due to some clever electronics, momentarily doubles the supply voltage at it’s output and then drops back to the supply voltage level.

I still have to locate a 230v ac solenoid for the decompression. I understand some older washing machines used one for the spin brake but so far I have not been able to locate one.

On the generator side of things, I have stripped out the top cubical, numbering all the wires as I went, and have cleaned all the components up ready to go back in. The starter solenoid was missing but I have obtained a generic starter solenoid that will fit in. Presently, I am freeing up some stuck brushes around the commutator, cleaning all the terminals as I go and verifying the integrity of the wires back to the cubical.

So, slow progress but at least it’s moving forward.
Dave

My Lister LD1 SOM did not come with a control panel and I have not been able to source one so far. I am fairly conversant with electronics so I have been toying with the idea of building a working panel from scratch using a mix of old and modern components where necessary. Hopefully, an original will turn up one day.

Has anyone been there and done that?

Here are some of the problems as I see it, and possible workarounds.

1.  Choke (CH) is a prominent part of the panel and plays an important role. This would be hard to replicate as it is unknown what material the toroidal core is made from. (I also note that different part numbers are given for the 12 volt and 24 volt chokes and it would be interesting to find out what the differences were. Maybe wound with different gauge of wire as the 1.5Kw generator outputs a max of about 6 amps whereas the 4.5Kw units puts out about 18 amps of current. Hopefully, someone may be able to explain the differences or take some measurements of wire diameter and toroidal core dimensions of both 12v and 24v chokes). Anyway, I would like to make a replica probably using an insulated core just for show and feed one turn only through a small current transformer and associated electronics to perform the same task as the original choke.

2.  The line contactor (LC) should be reasonably easy to replace with a modern relay with suitable contact rating if someone is able to measure the voltage across it's coil when the generator is operational, or, measure the resistance of the coil itself, please.

3.  Reset switch (K) - fairly easy to replicate it's function with a push button and timer/relay readily available and cheap.

4.  Detection relay (D) should be able to be replaced with any relay with a coil resistance of 100 Ohms.

5.  Meter - I should have something similar that I can modify and rescale.

I have attached the most modern circuit I have for the LD1 and SL1 generators. LD2 and SL2 circuit is very similar except for an extra resistor in the reset switch circuit and some difference in the wiring of the generator head.

Cheers from Australia
Dave

Hello Tony, I wonder how you went with the rebuild. I have and LD1 Startomatic with no control box. I have just received information on differences between the 12v and 24v control boxes.

The Ballast resistor BR is only used in the 24v versions to drop the voltage to the heating element in the reset switch only, nothing else.

Choke CH Has different part numbers for the 12v and 24v systems so obviously some difference there. There are also different part numbers between the 230v and 115v generators.

The line contractor LC also has different part numbers between the two versions. Coil winding have different part numbers and even the contact sets are different numbers, possibly heavier contacts for the 12 v version.

The DR unit you mentioned is not a resistance, it is a rectifier.

I would be interested to know the number of complete turns on choke CH in your control box. I have checked a 24v version and it has 42 turns of approximately 12swg wire. Also, if you can, could you measure the toroidal ring that the winding in on, please. I am looking for the outer and inner diameters (not including the wire) and also the thickness of the ring.

I am going to try to fabricate a facsimile of a control box and want to wind a similar looking choke but it will not be used for current detection, just there for looks.

Dave

Yes, I would be interested in your solenoid replacement method. Please post as I’m sure others would be interested as well

David

All ok, Bob. I managed to get that little pawl freed up today. Drilled up through the bottom and then was able to tap it out. Spring was nice and shiny so a touch up with wet&dry and it's all ready to go back together.

Do you know the stroke length of the original fuel control and decompression solenoids? I can probably find some modern solenoids to get me up and going for the moment and swap them out if I ever get original types. I can probable fabricate some covers if I can get some dimensions of originals. All the LD1 SOM photos I can find on the net seem to have round covers on both solenoids.

I am thinking of fabricating the wall mounted control panel as well but working out the inductance of that toroidal choke may be a problem. None of the circuits I've seen yet, seem to be a match for my 1961 LD1 SOM. I do have a manual printed in 1959 for 1.5 to 4.5kw soms coming so hopefully that will have a circuit close to mine.

All ok, Bob.
Ok, made some progress today. Removed the camshaft end cover and straight away noticed only one spring on the governor weights but the weights were free to move. Then found the missing spring at the bottom of the housing. Part of the hook on one end had broken off so I have fashioned another hook and that spring should be ok to reuse. Probably only lost half a turn.

Disconnected the linkages and found that I could jiggle the rack in the pump a bit but it would not slide. Took the pump out and using penetrating oil and judicious use of a nylon hammer was able to gradually work the rack back and forward until all of a sudden it got so loose that the rack would slide back and forward with it’s own weight. Thinking I may have stripped whatever it moved inside, I disassembled the bottom end of the pump to investigate. But all was well so I reassembled it and it’s now back in the engine.

Now on that spring loaded pawl, how did you get yours out. Can’t seem to budge mine. Does that little locating pin driven in from the side also retain it? If so, I’ll have to drill it out. Maybe also drill a small hole up from the bottom and drive the pawl out? That would leave a drain hole for future.

Cheers
David

Many thanks for the info. Unfortunately, all the solenoids and associated gear and linkages have been removed from the engine. When I got this unit, there was a 4 gallon galvanised sheet metal tank mounted there and what is there now is a Briggs and Stratton fuel tank that I fitted temporarily to get the engine started.

So that unattached throttle lever should find its resting position according to the spring tension on the adjustable rack push rod, is that correct? At the moment, I can move that lever back and forth without feeling any spring resistance. I will remove some of the covers and check a bit further so see what I have.

Cheers from Queensland, Australia.