Fotd 640 tractor

I've had a very long project and finally got it back together. I have an engine that cranks
with a starter so that's a good thing. Finally figured out that I had a faulty solenoid that
when the bolts were tightened, the engine would crank on it's own! I took that apart and
swapped the copper lugs with a spare solenoid and I'm in business. I see spark on a plug and
got it to back fire once but my question is this...Will these updraft carbs fire on ether if I
spray into the carb with choke and throttle open or do I need the gas tank and fuel? I may
try spraying into a couple cylinders by removing the plugs. I'm concerned that I have a weak
coil or something else going on that I'm not thinking about....I do have a new 6V battery. I
never removed the distributor so I think my timing should be good as long as I have the correct
firing order and the wires are on the correct locations. I put a charger on the battery last
night to get a high charge as I've cranked a bit....I have a picture of the old plug wires on
the engine so maybe I should review that to make sure even if I have correct firing order that
things are not rotated by a cylinder...make sense? Am I missing anything? Painted gas tank
yesterday so I can get to real fuel soon. thanks in advance, moday

It reads like maybe your 640 is cranking but not starting. Is that your situation?

My quick test uses gas in an old spray bottle, sprayed directly into the carb.

Yes it will fire on ether. There's a good chance you will bust the pistons trying to do it. What are you hoping to gain by trying to run it on ether instead of waiting until you have the gas tank on and fuel in it?

I know that it ran before it came to me but it had been a while. I did have it fire on gas/ether or some combustible before taking it apart. I will try not to use ether if it could really be damaging. To answer SHOWCROP's question, it does crank but not firing that I can tell at this point.

I don't understand how it even backfired once if there is no fuel in the system.

The compression ratio on your gasser is only about 7 or 8 to one.
On a typical diesel the compression ratio is double that.
I would say it is very unlikely you will hurt anything by giving it some ether. Even a bunch of it.
It is a diesel that you will bust stuff up internally with ether.
Not a gasser.
What says the gurus about that?

(quoted from post at 18:05:34 10/03/22) The compression ratio on your gasser is only about 7 or 8 to one.
On a typical diesel the compression ratio is double that.
I would say it is very unlikely you will hurt anything by giving it some ether. Even a bunch of it.
It is a diesel that you will bust stuff up internally with ether.
Not a gasser.
What says the gurus about that?

Click to expand...

I agree that ether is less likely to cause damage on a gasser, but you should still practice restraint in the amount that you use, and if there is no fuel in the fuel system then it will only cause combustion for a few revolutions at the most unless you continue to spray it, which I advise against, especially if it has backfired once already, or you could have your hand enveloped in a fireball. So use it to diagnose that you have a spark, but you will need to wait until the fuel system is operational before trying to do much more, like trying to time it or perform other diagnostics.

6V or 12V? ...Finally figured out that I had a faulty solenoid... - so was it the wrong solenoid? How did you deduce unit was defective? I doubt tightening connections caused starting on its own, likely incorrect wiring. Is battery good under load?


FORD 600/800 TRACTOR ELECTRICAL WIRING DIAGRAM:



Tim Daley(MI)

(quoted from post at 15:05:34 10/03/22) The compression ratio on your gasser is only about 7 or 8 to one.
On a typical diesel the compression ratio is double that.
I would say it is very unlikely you will hurt anything by giving it some ether. Even a bunch of it.
It is a diesel that you will bust stuff up internally with ether.
Not a gasser.
What says the gurus about that?

Click to expand...

Agreed, ether is problematic only when the force of compression is increased by the somewhat higher force of the ether explosion. It is hard to get high enough compression to have damage when you are starting out with the far lower gas engine compression.

to answer Tim's question about the battery, it is a new battery so I have assume it would be good unde load. I need to see if I have spark at all four plugs and I should check timing. The one thing I need to make sure is the firing order, I think it's 1-2-4-3 and is that counter-clockwise on the distributor? thanks in advance, moday