Ford 3000 runs rough

[davka]

My Ford 3000, 1966 model, gas, 3 cylinder was running rough. I put in new autolite plugs, new plug wires, new rotor, condenser and points. It is worse now, especially with open throttle. The bottom plate of the Holley Carb has been 'spitting' and it even spit out the gasket that was between the bottom plate and the carb. I reinstalled the gasket and it spit it out again. I attached a photo of the Holley Carb. On the photo, arrow #1 indicates the bottom plate (now without the gasket). Arrow #2 shows the broken gasket as it hangs below the carb.

Any suggestions on how to fix this problem? This was my first time doing a tune up but I think I got the gaps and everything right....but maybe not. The plug wires were difficult in making a secure connection on the plugs. Is the carb the most likely problem? I have a carb kit on the way. Thanks for any advice.

 

[davka]

I'm researching this and it might be described as a "backfire through the carb". That blows the bottom gasket out. What likely causes this?

 

[Roadworthy]

Have you considered adjusting the engine timing? It sounds as though it may be too far advanced. It's possible the advance is stuck. You may need to remove the point plate to check the flyweights for free movement or spring breakage. I think you're fixing the symptom without seeking out the problem.

 

[davka]

Have you considered adjusting the engine timing? It sounds as though it may be too far advanced. It's possible the advance is stuck. You may need to remove the point plate to check the flyweights for free movement or spring breakage. I think you're fixing the symptom without seeking out the problem.

Thanks for the reply. I will look at the engine timing next. Can you provide a little more info about how the advance might be stuck on a vacuum advance? My knowledge is limited but I believe the Ford 3000 is a vacuum advance. Flyweights and springs are in a centrifugal advance. Am I missing something? This area is really new to me.

 

[Roadworthy]

If you pull the point plate I believe you'll find flyweights in addition to the vacuum advance. If you have vacuum advance of course that could be stuck, too. Of course these things advance the timing if then engine is running so if timing is too advanced to start with they'd just make it worse. You could begin by static timing the engine - no timing light necessary for that. Check the dwell or the gap on your points. Be sure you check the gap when the cam in the distributor has the points maximum open. Are you certain the plug wires have it firing in the proper sequence? Firing order should be 1 - 2 - 3, the plugs should be gapped at about 0.025" and the point gap between 0.022" and 0.028" (TractorData.com Ford 3 tractor engine information)

 

[davka]

Thanks, Roadworthy. I will check everything you mentioned and, yes, the firing order is exact (1-2-3). I'll follow up. Thanks again.

 

[DJ54]

On my 2000 3 cyl., I had a similar problem about 15 years ago. If you look at a picture of the bowl gasket, you'll see multiple holes around the larger hole for the Venturi. I'm assuming from a previous backfire, before I got it, tore one side of that gasket loose, and pushed it back. I saw it as soon as I took it apart. I put it back in place, and sealed it with a small dab of #2 Permatex, just to see if it fixed the problem. I started it up, and it eliminated the problem. It's ran fine since then.

Since you already have the kit coming, be careful removing the bowl from the upper portion of the carb., to see it that one did the same. If it did, the new gasket in the kit should fix it.

 

[davka]

Re: Ford 3000 runs rough (backfire through the carb and spits out the lower gasket)

Hi all and thanks for the advice to date. Here is today's update: I checked the timing with a timing light. The timing process was not clear to me (saw different info in 2 manuals and couldn't really translate that to what I saw on the flywheel marks) but I did turn the distributor and saw a "2" on the flywheel; turned dist. and saw a "6"; turned dist. and saw a "10". None of the settings helped the engine at mid throttle idle. It still misses out. Please note that the engine runs very smoothly at LOW idle. Also, when I just touched the lever adjusting screw (it is on the carb left and behind the carb - see attached photo) it made the engine stumble and/or backfire. In summary, timing adjustments didn't seem to help in the engine performance at mid-idle.

Spark plug wires were double-checked and are in order (as 2 mechanics told me) (Firing order is 1-2-3 and number 1 from the distributor goes to the plug closest to the radiator). I plan to check the fuel filters, rotor for spring-back return, distributor flyweights, and possibly check the compression next.

Any ideas with this new info?

 

[lennyzx11]

Is the rotor pointing at number one plug wire with the #1 piston up at the top of the compression stroke?

Is the distributor turning a certain direction and the firing order is the same direction of rotation?
Distributor turning clockwise when cranked. Firing order set up clock wise also for your 1-2-3.

If you get a pop back through the carb “spitting “ than means a plug is firing with an intake valve open. This allows the explosion to travel back out the cylinder through the intake valve and out to the carb.

If you get a pop “backfire” out the exhaust pipe, the plug is firing when the exhaust valve is open. Allowing the explosion out through the exhaust valve and to the muffler/exhaust pipe.

Hope any of this helps.

 

[davka]

Thanks for the reply. I am new at this but I read everything I can on how to find TDC and I still can't find a precise way to do this. If you have guidelines I could sure use them and I will check the rotor. Question is: how do I get to or identify TDC. How would I determine which direction the distributor is turning? When looking at the engine with the hood open, the firing order printed on the engine is 1-2-3. However, I am told that #1 is nearest to the radiator. So #1 on the dist. is wired to the plug nearest to the radiator. Thanks again.

 

[lennyzx11]

To find out which way distributor turns.
Take distributor cap off.
Crank engine with starter.
Watch the distributor rotor to see which way it moves.

Google “how to find tdc on tractor “ for a lot of information.

My standard way to find TDC.

Remove distributor cap and coil wire.
Remove #1 spark plug.
Put thumb or finger over (NOT IN) spark plug hole like you are trying to stop a leak and have someone “bump” starter. (Alone can be done with a remote starter switch but be **** careful about neutral as this defeats the safety interlock)
As the #1 piston comes up, it will be pushing air against your finger.
Every other engine revolution will have a strong push then a weak push.
The strong push is the compression stroke. The weak is the exhaust stroke(exhaust valve is open).
Now we figured out we are on the compression stroke. If you know where your timing marks are, you can align them which means the piston is at TDC.
If you don’t know where your marks are, get a plastic straw and feel down inside the plug hole for top of piston. NO METAL LIKE A SCREWDRIVER! DON’T USE THE STARTER ANYMORE.

By hand, slowly turn engine by putting tractor in high gear and pushing or pulling it back and forth till that straw feels the piston at its highest point. That is TDC.

Look at distributor rotor.
It is pointing at where #1 will be.
Put #1 spark plug wire there.

Remember when we figured out the direction the distributor turned? The next plug wire goes to the next hole in that direction that the distributor is going to turn to.
(So if Firing order is 1-3-4-2 and distributor turns clockwise, the #3 wire goes in that next hole. Then 4 and then 2).

Notes
Setting the advance on the timing means turning the distributor slightly so that rotor arrives at that #1 wire just before the piston hits tdc.
If you got it all together right and try to start it and it backfires out the carb, you found TDC on the exhaust stroke.
This can be saved by moving the plug wires forward 2 spots on the cap in the direction of rotation on a 4 cylinder. One or two spots on your three cylinder.
That will put things in the right place.

Got kinda long winded there. Sorry.

 

[davka]

Lenny, thanks very much for the info. I will analyze it and proceed and report back. I do have a question about something you said earlier: you said the firing order was 1-2-3 and CLOCKWISE. My plug wires are set 1-2-3 but counter-clockwise; meaning that the number 1 wire is on the cylinder closest to the radiator, number 2 in the middle and number 3 is closest to the driver. Two mechanics have told me this is the way to wire the Ford 3000. I will check to see which way the rotor turns but can you please clarify? The engine idles smoothly at low idle but misses out badly at high idle or under a load. Thanks again.

 

[Texasmark]

After years of messing with spark engines, I finally developed a fool proof system for ignition timing. With everything in place, components replaces that needed be and all, I crank with a button in one hand and the other hand is on the distributor. I rotate it in both directions till it lights off and move it back and forth for the best running spot. Then when engine is warmed up, I turn the dist. CCW till it coughs, then CW till it coughs and set it in the center. Next I goose it to ensure it takes the throttle and lock it down.

 

[davka]

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.

 

[Gator6x4]

If you do not have a cylinder pressure tester buy one or rent one from Auto Zone. With the pressure tester in hand remove all the spark plugs and then check the pressure in each cylinder. I think you have a exhaust value problem. The exhaust gasses that should be exiting through the exhaust are blowing back through the carburetor. The throttle plate is restricting this escape route and the exhaust gases looking for an escape path is blowing the carburetor mounting plate gasket.

 

[lennyzx11]

Lenny, thanks very much for the info. I will analyze it and proceed and report back. I do have a question about something you said earlier: you said the firing order was 1-2-3 and CLOCKWISE. My plug wires are set 1-2-3 but counter-clockwise; meaning that the number 1 wire is on the cylinder closest to the radiator, number 2 in the middle and number 3 is closest to the driver. Two mechanics have told me this is the way to wire the Ford 3000. I will check to see which way the rotor turns but can you please clarify? The engine idles smoothly at low idle but misses out badly at high idle or under a load. Thanks again.

No. I’ll didn’t mean to infer clockwise. I’m sorry.
I only meant to to refer to whatever direction the rotor turns when you crank the engine.
If the distributor turns clockwise, firing order goes clockwise. And vice versa.

Firing order means what is going to fire next.
Your mechanics say the firing order is 123.
So that is what you follow around the distributor IN THE DIRECTION IT ROTATES.

Once that is set correctly and I say this only because you worked on it and a mistake may have changed the original factory setup due to misunderstandings, then I’d go to the next items that others have suggested. They are very valid.
Their (and I don’t mean to speak for them) recommendations are based that the timing and firing order is set correctly.

Point gap not correct could cause the symptoms you describe but only if we are sure that the first things like firing order and timing are correct to factory specs.

 

[davka]

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?

 

[Rebeldad1]

are you running fresh gas?
If its been sitting over winter... Ran fine last time before it was put away. Drain and fill with new. may help.

 

[davka]

Is the rotor pointing at number one plug wire with the #1 piston up at the top of the compression stroke?

Is the distributor turning a certain direction and the firing order is the same direction of rotation?
Distributor turning clockwise when cranked. Firing order set up clock wise also for your 1-2-3.

If you get a pop back through the carb 都pitting than means a plug is firing with an intake valve open. This allows the explosion to travel back out the cylinder through the intake valve and out to the carb.

If you get a pop 澱ackfire out the exhaust pipe, the plug is firing when the exhaust valve is open. Allowing the explosion out through the exhaust valve and to the muffler/exhaust pipe.

Hope any of this helps.

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

 

[kirkawilson]

Valves might be sticking in guides causing timing problems. Might want to pull valve cover and check both intake and exhaust valve motion.