Thank you Rome and Deas. That makes sense.

So that means my problem with spark is elsewhere.

I really don't think it's leads or plugs. They look good after being cleaned up.

Langdon

Hi, LangdonStevenson.
Yer welkum, Sir. How-wevver, bear in mind that without that switch connected, you would hafta explore 'other options' for shutting the pilot motor down WHEN you DO get it running. Things like pulling the spark plug leads, stalling it out at low idle with the starter pinion and clutch engaged or simply turning off the fuel and letting it run out.

If my memory is 'key-wrecked', Cat didn't want to make people's lives too easy when they placed those magnetos.

Just my 0.02.

yes the kill switch simply grounds out the magneto.
with no wire connectted to the grounding terminal it should work unless the insulator for the terminal is kaput.
cleean up the bolting face of the mag it should be shiny fine emery cloth works well for this. rub the area with no2b pencil clean the face it bolt to aswell and give it the pencil treatment too. they need good contact to work. the spark flow from the mag to the plug via the plug wire and back to the mag via the case and the engine casting
bolt it back on after cleaning the points rotor button and the rotor cap. try it again.

have you done a continuity(ohms) test on the plug wires?
if the plug ends arent insulated you can stop her by grounding the plug with a plastic handle screw driver the "fun" bit is you have to ground both plugs at the same time
it would pay to hook up the kill switch. do a continuity test on it too to check proper operation.

Magneto -

Trainkid88 suggests cleaning Magneto with no.2 pencil --- I am thinking he meant the eraser. Graphite pencil lead tracks will conduct the spark.
That was one of the "fine" tricks that were pulled on students when distributors were the normal on automobiles. a few pencil lines would really cause havoc in the firing order!

Inspect the bakalite cap for "tracks" and "cracks", be sure the brush and rotor are clean and no cracks in rotor. Those cracks can cause problems too.
Clean the points and make sure they open and close. If they do not open - the primary winding will not fall, thus the secondary will not produce the induction voltage.
(a simple trick Dad used when installing points --- wash them with starting fluid, it removes any oil contamination. There is a CAUTION in doing this --- be sure to allow all the vapors and liquid to dissipate before putting the cap on - a spark from the opening/closing of the points can result in a cap flying off or breaking into pieces!)
Any oil contamination can be source of insulation and also cause burning of the contact surfaces.

RE: Switch --- Most of the cats I operated did not have a functional switch --- those switches were known problems - especially when there was dew. WET SEAT meant everthing else was damp and as we all know, that moisture conducts electricity. Ground wire was usually cut off at the magneto or simply pulled off.

With all internal combustion engines --- 3 required items -- AIR - FUEL - IGNITION - Cut any one off and engine will stop.
Detroit 2 cycle were famous for having a "flapper" that cut the air off at the blower. A perfect example of how simple killing an engine is - cut off the air supply.

You might like to have the intake pipe open or at least a large plastic bag to cover the air cleaner when you first fire up the engines. If it wants to "run-away" you can kill it by cutting off the air supply.

Good Luck
CTS

Thank you Deas, yes my plan is just shut off the fuel and let it run dry. As far as I'm aware that's considered best practice anyway.

The magneto is pretty easy to access thankfully on this machine, so it wasn't a difficult job. You could even get the cap off and do the clean up with it still in place.

 

Langdon

Train kid - thank you for that explanation of the circuit involved with the magneto. I discovered that the battery in my multimeter was dead, so I couldn't do any electrical testing. Will be better prepared next time!

Langdon

CTS - Thank you for the suggestion about the plastic bag over the air cleaner to snuff the diesel. That's a neat idea.

I worked through your list yesterday on the magneto. Going to make a general post about it summing up the situation now.

Langdon

So here's an update on yesterday's efforts:

Starter motor:
--
 
Starter motor runs and cranks the pony motor but the bendix fails to disengage when you stop cranking, so the starter motor will stall the next time you try to crank it over. Don't know if the bendix is still to stiff or something else at play here.

The relay on the starter is bad. When energised it connects the power to the starter, but sometimes fails to disengage the power when the start button is released (took the start button out of the circuit and the problem persists, so I'm pretty sure it's the relay). I'm going to take the starter to someone and have it serviced.

Does anyone have a recommendation of who might be able to inspect and rebuild/repair the starter in NSW?

Magneto:
--
 
I pulled it off, removed the cap, cleaned the points (checked they are opening and closing), cleaned the rotor cap contacts, checked the brushed moved freely. All good.

Reassembled, remounted the magneto (including the manky metal gasket behind it - which I now understand is required for electrical connection) then cranked the starter.

I thought that nitrile gloves would be insulation enough, but apparently not. I'm pleased to report that I now have spark after receiving a belt in the hand from the metal end of the spark ug cable (subsequently retested with a leather glove and more circumspection, the spark plug is cheerily sparking away).

So I'm calling that one fixed enough for now.

Fuel:
--
 
 
Next challenge is the fuel system to the pony motor. The tank wasn't too dirty. Cleaned the glass bowl below the tank. Removed the glass holder and removed some old varnish from its inwards. Reassembled everything. Turned on the stopcock on the tank and got a slow trickle of fuel into the bowl.

Pulled the fuel line (which has an inline fuel filter) off the carburettor and got a trickle of fuel there.

So that seems ok for now. Fuel is getting through.

I cranked the pony motor over with a pull rope but got no sign of life. So I'm thinking the carburettor might be gummed up.

Should I pull it off and give it a clean?

I've given the choke mechanism (that was very stiff) lots of WD40 and it's moving much better. That could be a candidate for the pony motor "low power" issue if the choke wasn't turning off when it was pushed in.

I actually can't see how I'd get the carburettor off without pulling everything off the top of the pony motor. That's a bigger job than I have time for this morning, so I might have to leave it until next time. With a little luck the new fuel in the system may unblock it - or it might make it worse too I guess. Have to wait and see.

Other:
--
Gearbox/final drive oil looks good. Up to the full mark, clean, no sign of water or sludge. So I'll leave that be until I get the diesel running and know its worth investing the money in replacing it.

That's all for now. Going to pack up and head back to Sydney. Get the starter serviced then come back and try again.

Langdon

You did check that the timing was correct when you replaced the magneto?
Just below the magneto is a small gearbox, you should ensure it is full of oil too.
Is there any way to drain the float bowl on the carb? Been too long since I was around one to recall.
If there happend to be any water at all in it, that will stop the function of the carb and jets.
You will have to ensure the needle valve and float are allowing fuel to fill the bowl. You will know if you have a "plug" in bottom of float bowl or if the float,needle do not seat, it will flood.
Be sure you have no gasoline leaks - a fire is so easy to start with a leak. Fire extinguisher is a good idea to have at hand.
Might end up pulling the carb.

CTS

Hi CTS - regarding the magneto timing I don't know if I got it right or not and couldn't find anything in the books, or markings on the magneto or the drive block in the gearbox to tell what the orientation should be.  So I put it back together and when I can crank it easily will just check that I get spark on the compression stroke.  Best I can do without some more intel from more knowledgeable members for now.

Thank you for the tip about the gearbox below the magneto - I think I see what you are referring to, is this it circled in the photo?


Regarding the carburetor, it's really hard to get to anything on it as it's tucked under the diesel engine air intake pipe and the fuel tank.  I could *just* get to two bolts in the bottom of the carburetor though.  I unscrewed them a little and got fuel out of at least one of them, possibly both but I don't remember now.  Certainly wasn't any water in it anyway.

I will take a fire extinguisher with me next time, thank you that's a good suggestion.  The whole system seems fuel tight though so far.

Yes I'm thinking that next time I might bite the bullet and just pull the carburetor (and everything else I have to take off to get to it) and give it all a good clean.

Langdon