I don't know anything about the LD1 Start-O-Matic, but I have a SR-1 remote start
Kohler generator and have a lot of trouble with the solenoids.  I ended up replacing
the decompression solenoid and doing extensive modifications to the fuel solenoid.

1. Decompression Solenoid

Specifications:
* Type: pull
* Power: AC (not DC!)
* Voltage: your generator's single-leg AC volgage (120 VAc in USA)*
* Frequency:  your generator AC frequency (60 Hz in USA)*
* Duty cycle: continuous (energized whenever engine is running)
* Stroke: ___  inches**
* Force: :  ___ foot-lbs (decreases with distance)**
* Mounting bracket: ______**
* Fastener at end(s) of core: _____**

** Measure for your engine and control linkage.

On the SR-1 Kohler (and I suspect on the LD1) the decompression  solenoid is AC-
powered.   When a certain RPMs is reached, the AC from the generator has enough
power to close the solenoid (which is pulling against a spring plus friction).
The solenoid must be mounted with the core vertical, so the core moves up.  This
motion must be translated by a linkage into whatever motion you need to do what
you do when you manually disengage decompression.

The linkage on the SR-1 is as follows (motions given for start up--shut down is the opposite):
Solenoid -- electromagnetic pull
Core (moves up) -- clevis pivot to
rod  (moves diagonally up) adjusteable-length clevis to
pivot -- lever (tilts) connected to
shaft (rotates clockwise seen from outside end) passes though housing --  connected to
lever (tilts) -- clevis to
rod (pulls away from head) -- clevis to
decompression lever -- affixed to
shaft -- passes though head cover -- affixed o
pin -- slips off top of
exhaust valve stem
This allows the exaust value spring to close the exaust value when rocker
releases it on the compression stroke so the cylinder can fire.

(It might be possible to replace the linkage from the solenoid core to the deompression
lever with a mechanical cable, but this would change the sroke might change the amount
of mechanical advantage.  But in your situation, it might be worth a try.)

According to the manual start instructions for the SR-1, the engine needs to crank freely
3 to 20 turns  (depending on the ambient temperature and how long the engine has been sitting).
So on startup. you don't want the decompression to release too soon

On the SR-1, a torque spring located on the shaft where it emerges from the side of the housing
pulls against the solenoid.  It is this spring that is responsible for re-engaging decompression.
Since this spring is not adjustable, I disconnected it and added a tension spring attached to
the decompression lever on the head instead.   http://listerengine.com/smf/index.php?topic=8811.0

At shutdown,  the generator spools down and the AC power declines. At some the return spring
can overcome the solenoid,  and the linkage moves back.    This brings the decompression
screw into contact with the edge of the exhaust valve stem.  When the rocker pushes the
exahust valuve open, the smooth end of the decompression screw slips onto the top of the
valve stem, holding ti open.


2. Fuel Solenoid

Specifications:
* Type: pull
* Power: DC
* Voltage: 12-14 VDC
* Duty cycle: continuous (energized whenever engine is running)
* Stroke: ___ inches**
* Force:  ___ foot-lbs (decreases with distance)**
* Mounting bracket: ______**
* Fastener at end(s) of core: _____**

** Measure for your engine and control linkage.

The fuel solenoid is quite different: it is DC powered.  AC and DC solenoids are not
interchangable.  A DC solenoid hoooked up to AC would buzz.  AC solenoids
have a laminated core with a conductive ring around it that creates a second pole
that is 90 degrees out of phase.  This keeps the solenoid close thoughout the AC cycle.

One problem with all solenoids is that they don't force when the core is fully extended. 
So it's a good idea to keep the stroke as short as feasible, and to use mechanical
advantage during the first part of the stroke.   However, the fuel solenoid has to move
the entire rack.

To overcome this, the fuel solenoid on the SR-1 has a "helper coil" that pulls more
power than the main coil.  When he solenoid is first energized, the helper coils
is on, giving an extra pull to core.  After the core moves fully inside the solenoid coil,
it opens a leaf switch, disconnecting the helper coil.

Important: the helper *must* be shut off -- it ir remains on the wire in the coil will
overheat and melt (usually at just one spot).  So you must make sure that nothing
prevents the core from slamming into the switch and opening it.  Fore xample, if
there is a manual override that positions the staring solenoid int he "on" positoin,
the linkage must be adjusted to make sure that the core is fully inserted in the coil
and firmly holding the switch open.

SR-1 START sequence of events:
1. Engine  at rest state:
   * no engine motion
   * decompression engaged
   * rack in shutoff position (all he way to the right)
   * Control lever in START position (i.e, not latched on auto-start models)
   * Relays open, no current flows
2.  Remote or local START switch closes
3. Certain relays close
5. Fuel solenoid: normal and helper coils energize
4. Fuel linkage moves, rack pulled to START position
5. Fuel solenoid ore pushes switch open, shutting off helper coil.  Main coil still energized.
6. Field coil and DC commutator energized: generator unit functions as DC starter motor
7. Engine and generator spool up: 3 to 20 full cycles
8. Decompression solenoid overcomes return spring, linkage moves decompression lever
9. Exhaust valve closes on compression stroke, engine fires
10. Engine and generator come up to full speed as
11. Governor moves rack to the right, decreasing amount of fuel
12. Fuel solenoid linkage to control lever to RUN position
     (= latched on remote-start model).
 
SR-1 STOP sequence of events:
1. Engine  running: state
   * engine and generator turning over at design RPM
   * decompression disengaged
   * rack under governor control
   * Control lever in RUN position (i.e, latched on auto-start models)
   * Certain relays closed, DC current to fuel solenoid (main coil only)
      and generator stator coil; AC current to decompression solenoid
2.  Remote or local START switch opens
3. Certain relays open
4. Fuel solenoid:de-energized
5. Fuel linkage moved by spring, rack pulled to STOP position, unlatching control lever
6. Firing ceases.
7  Engine and generator spool down
8. Decompress solenoid overcome by return spring, linkage moves
9. Decompression pin in contact with edge of exhaust valve stem
10. Rocker allows exhaust valve to close, decompression pin slips onto top
    of valve holding it closed
11. Engine motion ceases
12. Shutdown state: No AC voltage.  No battery current flows.

Much trial and error will be required to get any non-exact replacement solenoid or improvised
linkage working--but it's quite possible to do.  Good luck!

That's a great idea to have a tee to the return line, Mike,
I suppose you had to fill the tank one quart at a time in order
to calibrate the gauge.

I like sight tubes--I just wasn't sure what clear, rigid material
to use.  Or how to build one that wouldn't leak.  I didn't think
of using two tees.

I had a short section of clear vinyl installed as a sight tube
at the pump inlet for a while, to watch for bubbles..  But it leaked,
so I removed it. Probably I used the wrong barb fittings.

I find dipsticks can be hard to read in dim light.  Sometimes I even
have trouble reading the Lister dipstick after an oil change.
Over the years, the matte finish on has erroded at the oil line. (Wish I
knew how they created that finish on steel: sandblasting?   Chemical
etching?   I'd like to renew it, since I can't buy a new dipstick.)

Delo Super 1300 contains something (a dye?) that fluoresces weakly
in UV light.  I used a UV LED light for a while but it didn't help much
and was a lot of bother.

But the worst problem is that when I pour the motor oil into the filler
on the head cover, it takes a while to percolate down to the crankcase.
So It's easy to overfill the engine.

I finally added a quick drain on the crankcase, so small overfills can
be corrected easily.

This simple SR-1 field modification makes the decompression springg tension adjustable. 
See photos.

It may be of interest to anyone who had to replace the decompression solenoid and wasn't
able to find an exact replacement.  It also may help anyone who finds the decompression
release won't disengage in cold weather or won't re-engage in hot weather.

The solenoid pulls to disgage decompression, but relies on the spring to re-engage
decompression.  The spring tension must be enough to pull the decompression control
upright, but not so much that the solenoid cannot overcome it.    The less powerful the
solenoid (or longer the stroke), the more delicate the balance.

The stock torsion spring (located located on lever on side of solenoid housing) isn't adjustable.

To use the added spring as a helper spring, leave the existing torsion spring (ttached.

To use the added spring as a replacement spring, unhook the existing torsion spring.

Hope this is useful to someone.

I took some more measurements of rack motion, but none of them are accurate enough to risk
making an adjustment.    It looks ballpark, and the engine was running OK before the fuel injector
pump clamp bolt worked loose.  So I've decided to leave the locater plate set where it is.  Thanks
anyway oldgoat.

I'm almost glad I took the front cover off--it's a beautiful casting. I wouldn't have noticed otherwise.
I read somewher that in 1938 R. A. Lister built an advanced mechanized foundry at Dursley,
and that the coke-fired furances were replaced by electric furnaces in the 1970s.

Looks like I'm going to need to replace the camshaft oil seal.  There's nothing left of the rubber except
a tiny bit around the front.  Should have been replaced in the rebuild, but obviously it wasn't.   

It's a Gits type.  All I have is a useless Kohler P/N, but a supposedly compatible one is available on-line
and gives the Lister P/N as 201-13190.   Anybody know if this the right number for the SR-1 gear-end
crankshaft oil seal?

Looks like it's necessary to pull the bronze bushing out of the front cover in order to replace the oil seal.
Anybody know if that's correct, and what kind of puller to use?   Do I need a hydraulic press to re-install
the bushing?

I trashed the paper gasket removing the cover--it was stuck to both sides.  I have to get this engine running
before the next big storm, so I had to use Napa gasket-maker.

I was able to guide the speeder screw (with spring hooked) though the hole in the cover using a 4-claw flexible
gripper.  Only took three tries.    Getting the solenoids lifted up a fraction of an inch so the cover could slide
under them was made easier by gentle use of a pry bar.

I have to say that running a screw attached to a spring though a cover is almost as annoying as mounting
control solenoids to one.  Does the word "cover" (as in "remove the...") mean something different in Gloucestershire? 

Not your fault, oldgoat.  I should have mentioned that the engine had been smoking and seemed
to have diminished horsepower.   But because those are also symptoms of a bad governor, I
jumped to that conclusion in my first post.  My mistake.

Does anybody happen to know the procedure for calibrating the locating plate adjustment
(which sets the maximum rack movement) on an SR-1 equipped with remote start?  I'd like
to check it before buttoning up the engine.

The procedure in the Lister *Instructions* book only applies to the manual start models.
The Kohler book just reprints the text and diagram from the Lister book.

The locating plate has the same adjustment, but there are no external stops on it and instaed of a
control lever, it has a latching mechanism with a cam that is connected to the fuel solenoid.  It makes
the same start-run-stop movements, but there's no obvious place to put a shim or take a measurement.

My attempts to get a precise measurement of rack movement were not successful. There's no room
to get any kind of measuring device onto the top of the rack inside the housing.   I tried making a special
clamp to mark the position of maximum left travel,  then measuring the distance between the clamp and
the calibration mark with a feeler gauge.  But I can't see the end of the feeler gauge or tell if it is flat. 


There must be some way that they adjusted the locating plate at the factory--it's just not in the books
I have.  The Lister book only covers manual start models, and the The Kohler book reprints the diagram
and procedure from the Lister book (even though many of  these generators were sold with remote start).

I considered drilling a hole in the housing opposite the free end of the rack, then inserting a depth
micrometer.  Afterwards, I could tap it and screwing in a oil-tight plug.  But I'd hate to have any metal
filings drop into the crankcase, and anyway I don't like making field modifications that are irreversible.

BTW, it seems odd that the tolerances on the rack should be so tight: 0.046" - 0.052" with the upper
limit not to be exceeded.   If I want to aim for the upper half of the range, say 0.050", then to be safe
I need to measure with an accuracy of +/- 2 thou.   Obviously, the fuel injector pump that Lister used
was  designed for a bigger engine.   Maybe there wasn't an off-the-shelf one small enough.

If you still haven't find a non-running SOM to use for parts and want to try  making an automatic
compression release, this might be relevant:

I replaced the decompresion solenoid in an SR-1 with one made for a pellet stove (washing
machine are another possible source).   It took a lot of mechanical adjustment to get it working
just right.  I imagine it would be about the same on an LD-1.

If you or anyone is interested is building an automatic compression release or replacing an
existing solenoid that is no longer available, I can post more information.

Thanks, oldgoat and ajaffa1. That's all super helpful--especially
the great photos!

On this engine, the front cover is attached to the speeder spring
by the speed adjusting screw.   The threaded end of the screw
emerges the from a threaded bushing screwed into the door.

Do I need to first remove the fuel pump housing door in order to
unhook the other end of the speeder spring from the governor link,
before removing the front cover?   Or is there some other trick?

Here's what I tried:

First, i measured the protruding portion of the screw, so I'd have
some way of re-setting the speed roughly correct.

Then, I tried unscrewing the bushing from the front cover, cleaning up
the threads on the adjuster screw, and trying to run it back though
the  bushing.  But it only moved about two turns.   The problem is
that the external threads are beat up and there is nothing to grab
to apply torque --- the entire accessible portion of the screw is
threaded.

I tried running two nuts onto the the end of the screw and jamming
them together.  But I'm afraid to turn any harder for fear I'll shear
the screw (it's only #10 x 32 -- I think).  So I sprayed the nut/bushing 
with penetrating oil (PB Blaster)  and I'm going to let it sit overnight.  .

I've adjusted the governor speed in the past, but only by less
than one turn.  It seems possible that no one has taken the screw
all the way out since the engine was manufactured.   The fuel
pump door isn't too accessible in this installation, so I sure hope
I don't need to remove it.

Sorry to ask such boring questions..  I'm sure it will get more interesting
once I get the cover off.

Hello, all!    I have a SR-1 that I purchased new back in the 1970s.   It's been overhauled twice,
most recently about 1  year ago.    I do all the other maintenance and repairs.   I'm hoping that
someone here has seen the following symptom:

The governor has stopped working.   The engine doesn't overspeed, but the speed wanders
and RPMs decrease with load.   Onset of problem was gradual.  Engine starts and stops just fine.
Fuel supply is fine, air intake is  unrestricted and exhaust is unrestricted.

With the engine stopped, I removed the access door to the fuel injector pump.  WIth the control
manually set to the RUN position, the mark on the rack lines up with the right edge of the fuel
injector.   Using a screwdriver to gently slide the rack to the right, it seems to move freely and
I can feel the tension of at least one spring.

I am able to measure the engine speed because this engine is part of a Kohler generator set, and I
have a vibrating-reed frequency meter on the AC output.  I am not using the engine except for
very light loads until it's fixed.  We have a solar power system, but this generator is our main source
of AC power for household use and the well pump during the winter months.

The engine itself has been highly reliable (unlike the electro-mechanical stuff made by Kohler).   
However, the remote start -- which replaces the start-run-stop handle with a mechanism--seems
to be working.  I'm posing in this engine forum because it seems to be an engine problem, not
a control system problem.

Any ideas or suggestions, anyone?   Thanks!