Can't make the slightest incline after tune up work

sald · Jul 20, 2018

1940 Farmall A

I just posted something about brakes but now I have bigger trouble.
I rebuilt the Zenith Carb (with main jet needle) and just changed the needle and seat as well as added the return clip on the needle. Everything else is the same just cleaned. Starts and purrs. 1 1/2 out on the idle screw, 3 turns out on the main jet and the idle stop screw keeps it about 600rpm (Tach doesn't work correctly).
Points, Cap, Rotor, Capacitor and wires all changed.
The day I got it it felt like it was going to stall on the minor (very minor) hill by my house. Now it dies on the same hill.
Any help would be appreciated. The governor seems to be working the engine just seems like it is starving even with black puffs of smoke the rpms drop and then dead.

Janicholson · Jul 20, 2018

It should not slow down and die with excess fuel unless it was way rich. It might be timing, including the centrifugal advance
failure causing low power. Jim

David G · Jul 20, 2018

The timing will be off if you gapped the points wrong.

You can tell slow timing, it sounds blah, correct timing sounds staccato.

sald · Jul 20, 2018

I think I set the points correctly. I did remove the magneto after marking where it was at before hand. I am going to use my timing light tomorrow and see what is up. Do I need to do a static timing adjustment first or just go to the timing light? Also from an idle to fast throttle I should see an advance in the timing on the light correct? What degree bore TDC?

ih560 · Jul 20, 2018

You want to set the magneto to where the impulse coupling trips right at TDC on the compression stroke.
I've always had luck by rotating the magneto so that rotor is pointing right before #1 cylinder. Have the engine slightly before top dead center, install the mag, but don't tighten the bolts. rotate the engine until top dead center #1 compression stroke. Now slowly turn the top of the magneto towards the engine until the impulse coupling snaps. Tighten down the bolts and you are set. If there is any chance you will ever hand crank it, set it this way.

sald · Jul 20, 2018

Turn the magneto toward the engine?

rustybronco · Jul 20, 2018

(quoted from post at 18:17:13 07/20/18)
The day I got it it felt like it was going to stall on the minor (very minor) hill by my house. Now it dies on the same hill.

tart with the basics. It did it when you got it and it's still doing basically the same thing after you worked on it.

Check compression.
Check the point gap.
Check mag timing.
Check spark colour while it's running by inserting a screw driver into one of the plug wires and hold near the block.
Does the mag 'snap' when bringing the engine to TDC. (Checking impulse coupling)
Check float level.
Drain and repace fuel if quality unknown.
Use choke to determine if it's running lean or rich under load.

About your brakes, remove wheel-tire-weight then remove the final drive. Making a platform that you can place the final on which will roll around can make removal and replacement so much simpler. I used a milk crate which had casters on it and added a wooden platform to the top. Then it was a simple matter to raise or lower the the tractor as necessary in order to slide the drive in and out. You could make similar with four casters and a bit of wood.

ih560 · Jul 20, 2018

There is a small amount of rotational adjustment, rotating the top towards the engine advances the timing. You get the engine at TDC and the magneto right before #1, then when you rotate the top of the magneto towards the engine, it will advance until the impulse couple snaps. This will set it at 0 TDC. This is all done without the engine running of course.

sald · Jul 20, 2018

Ok, just wanted to make sure.
How do I make sure the spark is advancing? I assume with the timing light, but how many degrees and if not what then?

ih560 · Jul 20, 2018

The magneto advances 30 degrees and It does this when the engine is running. You can check it with a timing light that has an advanced setting.

gene bender · Jul 21, 2018

you are going to clean the flywheel so you can see the timing marks they are hard to find but are there and no
there is no advance when engine runs the mag goes to 33deg at all speeds only way to change timing on the mag is
to remove the front and move the gear that drives the rotor

sald · Jul 21, 2018

Working on it now. Cant seem to find the marks.

rustyfarmall · Jul 21, 2018

Black puffs of smoke indicate a too rich condition. Too much fuel. I think your adjustments of the idle screw and load screw are spot on, but did you check the float level? Did you inspect the float to make sure it does not have a pinhole?

pinball · Jul 21, 2018

If it were mine the firs thing I would do is remove the gas line from the carb. blow air back up the line then where the gas line goes on fill it with w-40, put the line back on and try it. if it were mine.

sald · Jul 21, 2018

Ok. Definatelty timing. At rotational limit and still firing retarded. someone messed with the rotor indexer on the front of the magneto. Just have to figure out how many teeth i need to move.

rustybronco · Jul 21, 2018

https://www.youtube.com/watch?v=0uIVu2SPRuY 11:25 mark

Or as Gene said in another thread "Just line up the gears so when the impulse trips the rotor is lined up with the plug terminal on the cap."

Further info... http://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=farmall&th=539604

.

rustybronco · Jul 21, 2018

The Mag does trip when you rotate it with the cylinder at TDC correct? The positioning of the Mag is what sets the timing. Points are set correctly yes?

David G · Jul 21, 2018

Mags are always fully advanced unless impulsing.

I would want to see about 30 degrees advanced, someone may have the specifics.

I would not worry about TDC if it is electric start, it is OK to advance that a couple degrees on initial if so.

sald · Jul 21, 2018

Guys! I should know better being a network engineer... I found the markings and found the magneto rotor indexing was off, fixed that. I could not time the engine BTDC only ATDC. Anyway, was going to give up when I thought to look at the firing order. Yup, I went ahead and changed the wires and cap last week assuming the last guy had them in order, well they were off. Amazing! Starts right up and goes up the hill no problem. Thanks!

David G · Jul 22, 2018

Great news, you should be able to hear the difference in the tone of the engine.

sald · Jul 22, 2018

Oh yes. Amazing difference. Also put in 3116 plugs.
Final question...
With timing light I am getting about 22-25 degrees BTDC at idle and wot. Should I advance it to get 30-33?

Janicholson · Jul 22, 2018

You can, but if you ever crank it with a hand crank you may be wounded. If it trys to turn backwards when cranking, retard the
timing till it no longer does that. Jim

Can't make the slightest incline after tune up work

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