Ford 3000 runs rough

[Gator6x4]

Gator,
Thanks for the note. You make a good point. I will check the compression next. Each cylinder has an intake and exhaust. How would a compression reading tell me that the exhaust valve might be set wrong or stuck? Do you know what a good compression number should be for the Ford 3000 gas?

If you have a exhaust valve stuck or not opening far enough, that cylinder will give the highest reading, well above the reading for the other two cylinders. A blown head gasket on the exhaust side will also divert exhaust gases into the intake.

 

[lennyzx11]

Lenny: If this is the case, what would be the remedy? Check the valve clearances, broken springs? Or something else? Thanks.

Another long winded explanation post. You all have been warned.

First is getting the timing set.
If the timing or wiring is off, the plug fires at the wrong time while a valve either intake or exhaust is open. We’ve discussed that ad nauseum.

If a plug wire(s) are not correct, then the rotor will line up and fire the wrong plug at the wrong “time” (hence the word “timing”).

Example
Say you wired it backwards to the rotor rotation.
Firing order is 1-2-3. But since the rotor is turning the opposite way, the rotor is going to line up in order of 1-3-2.

Plug fires at number 1. Both valves are closed. Piston is near top on compression stroke. All is well.

Rotor moves to next plug. Supposed to be #2. But it is connected to #3.
Well, 3 isn’t ready yet and is still on its intake stroke going DOWN. The Intake valve is OPEN drawing fuel/air mixture from carburetor.
Spark explodes and the fire/explosion travels back through intake valve which is open out to carb.

Rotor travels on to what is supposed to be #3. But it’s connected to 2.
2 cylinder missed its spark (went to 3 remember?)
So it has went over the top of the compression stroke went down on its POWER stroke and is coming back up on the EXHAUST stroke.
Exhaust valve is open to let spent gassed out.

(Extra useless info alert. The camshaft is turning only 1 time to the crankshaft’s two times. That’s why there are two strokes there of the crankshaft. The distributor is turning in relation to the cam shaft 1:1 while the camshaft is in a 1:2 ratio with the crankshaft).

Meanwhile, back at the ranch.

And here comes the rotor and fires what it thinks is #3 but it’s actually connect to #2.
Plug fires on the exhaust stroke, piston can’t go down (the crankshaft is forcing it up, the exhaust valve is open and so the fuel air mixture that never got burnt before explodes and pushes out the EXHAUST valve to the pipe for a “backfire” out the exhaust.

Sequence of events.
Rotor moves to # 1 plug wire at same time as #1 piston is at TDC of Compression stroke.
All is well and the stars are all in place in the universe so piston is driven back down correctly keeping the engine “running” under its own power.

Then when that 2nd plug (which is actually #3 Cylinder fires at the wrong spot, that piston is on its down on the intake. Intake Valve is Open. Engine gets a little more “nudge” to keep running with Piston already going down and the explosion above it.

3rd plug fires. Which is connected to #2 CYLINDER. it’s past it’s compression and Power Stroke and on to the EXHAUST stroke. It missed it’s chance since #3 cylinder got the spark supposed to come to it at the right “time”.
Inertia carries through the stroke and till 1 bangs again to repeat the cycle.

Clear as mud?
This would be a better explanation if you were here next to the wood stove here in my shop over cold beers like I am (well coffee... it’s still a little early for Sunday beers even for me! Better give it a couple more hours at least.)


When that is verified as correct, then you go into all the tests/ checks others have mentioned. They are right.

 

[davka]

Hi all, thanks for the good advice to date! I am slowly checking through every suggestion.

So far, the engine idles smoothly but sputters, misses and backfires through the carb upon acceleration and at med to high idle. I'm reading that the accelerator pump can cause this. Anyone have guidance on how to identify and clean or adjust the accelerator pump?

 

[Gator6x4]

Hi all, thanks for the good advice to date! I am slowly checking through every suggestion.

So far, the engine idles smoothly but sputters, misses and backfires through the carb upon acceleration and at med to high idle. I'm reading that the accelerator pump can cause this. Anyone have guidance on how to identify and clean or adjust the accelerator pump?

Well since you do not want to check the engine cylinder pressure, get a common kids ballon. Stretch it over the top of the carburetor while the engine is running in the sputter mode. If the ballon inflates, you have a severe blow back problem and regardless Of what you do without correcting that problem, your problem will still exist.

 

[Gale Hawkins]

New distributor cap?



Tractor engines typically don't have accelerator pumps.

My tractor shop replaced the points with electronic ignition system on a guy's late 60's 3000 with good results. He said do not go with the cheaper ones.

He just put the electronic ignition system on my 1948 Allis Chamber and now it will idle at a stable speed.

Per this guy some points will last for years and others are bad out of the box due to they are outsourced these days.

 

[Texasmark]

Texasmark, I basically did what you are suggesting. It's good to know that system works. Do you think the problem is with the Holley carb, the distributor or the valves? The engine idles smoothly but misses out when I open the throttle. I am trying to decide what to investigate next. Thanks for your note.

Set the timing a little faster than centered, till it takes throttle. Next could be centrifugal spark advance...weights down in the distributor below the points mounting plate sticking,or too lean a carb setting on whichever jet has the most effect, if equipped with low AND high speed adjustable jets, or dirty carb. would be my choices.

 

[Texasmark]

Texasmark, I basically did what you are suggesting. It's good to know that system works. Do you think the problem is with the Holley carb, the distributor or the valves? The engine idles smoothly but misses out when I open the throttle. I am trying to decide what to investigate next. Thanks for your note.

Backfiring is intake valve open during power stroke.....could be timing off or stuck/mal adjusted intake valve.....or on higher compression engines could be glowing carbon on top of the piston setting off the charge before it's time.

Otherwise, set the timing a little faster than centered, till it takes throttle. Next could be centrifugal spark advance...weights down in the distributor below the points mounting plate sticking,or too lean a carb setting on whichever jet has the most effect, if equipped with low AND high speed adjustable jets, or dirty carb. would be my choices.

 

[davka]

Today I overhauled the distributor. Completely removed it from the shaft housing and disassembled it. I checked the fly weights and springs and all seemed ok. Cleaned and lubed and reassembled and re-set the gap on the points.

I will check the timing and then move on to the next potential trouble spot: The carburetor.

The Ford 3000 Shop Manual was an accurate guide on overhauling the distributor. I hope it will be as accurate on the Carburetor.

A few days ago I took the Sediment Bowl off and cleaned it. I noticed that it was missing the Filter and it had rust colored sludge in it. I have ordered a new Sediment Bowl. I wonder if some of this debris is in the Holley Carb.

If the Carb is not the problem I guess the only other things to check are the Coil and the Valves.