# Ford 3000 runs rough



## Dkat (Nov 28, 2019)

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.


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## pogobill (Jan 31, 2012)

I'm wondering, with the info supplied, if the timing is off. When ever you change the points, you should check the timing of the engine. Never heard of this problem but almost sounds like the engine is firing before the intake valves are closed. I could be way off, but there are some handy fellows here, that I'm sure will help you further.
Welcome to the forum.


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## Dkat (Nov 28, 2019)

I intend to check the timing. But it was running rough before I changed the points. The rough, missing out started kind of suddenly a few weeks ago. Thanks for the reply.


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## FredM (Nov 18, 2015)

I would be inclined to check moisture in the fuel which is an easy first up check, then I would check the valve clearances, then timing while the valve cover is off, you could also have a sticking valve which will show up when checking the valve clearances.


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## FredM (Nov 18, 2015)

another thought would be if you have any practical jokers and they switched a couple of plug leads, this will give good backfires too and make the tractor run very rough, have you checked the HT leads for being correct on the spark plugs?.


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## Dkat (Nov 28, 2019)

Hi Fred, thanks for the reply. I checked everything you mentioned (moisture, plug wiring) and all are ok. I will try to check valve clearances and timing as a next step. I just don't know what can cause backfiring through the carburetor.


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## deerhide (Oct 20, 2016)

Dkat said:


> Hi Fred, thanks for the reply. I checked everything you mentioned (moisture, plug wiring) and all are ok. I will try to check valve clearances and timing as a next step. I just don't know what can cause backfiring through the carburetor.


I will suggest this; with the engine running a bit above idle, good rubber gloves on and not touching any other part of the tractor pull a plug wire off(either from the plug or distributor cap). If the engine stops right away I would tend to believe the plug wires are on wrong, if it keeps on running but rough it's something else like a stuck valve. BTW did you do a compression check?


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## Dkat (Nov 28, 2019)

deerhide said:


> I will suggest this; with the engine running a bit above idle, good rubber gloves on and not touching any other part of the tractor pull a plug wire off(either from the plug or distributor cap). If the engine stops right away I would tend to believe the plug wires are on wrong, if it keeps on running but rough it's something else like a stuck valve. BTW did you do a compression check?


I have not done a compression check. Is that the best way to determine if the valves need adjusting?


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## FredM (Nov 18, 2015)

a lean running or dirty carby will cause backfires too, check the valve clearances first before a compression check.


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## Ultradog (Feb 27, 2005)

You've had some good advice above. Always, always check your spark first. If you are satisfied you have good spark at each plug then go on to fuel.
Remember that there are 3, sometimes 4 fuel filters on your tractor. First one is a screen on top of the shutoff valve at the bottom of the tank. Second one is a screen on the top of the fuel pump behind the radiator. Next one is in the sediment bowl behind the carburator. Last but not always is a scintered brass screen in the fitting where the fuel line goes into the carb.
That is a good, reliable fuel system but it does need maintenance (cleaning) on occasion.
That brings us to your Holley carburator.
I hate those bloody Holleys and have messed with a few of them.
If you are a really Good carb man you can sometimes rebuild them so they run right. 
Myself, I like to pretend I'm Tom Brady and give them my very best heave into the nearest swamp, dumpster or scrap pile.
Then I buy a Zenith carb. They are expensive - $4-$500 but with a clean fuel system as I described above they will make your tractor RUN.


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## Ed Williams (Jun 13, 2019)

Backfire thru the carb is good indication of an open intake valve during cylinder combustion. This can be caused by many factors including a burnt valve, stuck valve, broken valve spring, timing, etc,etc. First step is to run a compression test to identify which cylinder is causing the problem, then check timing, then check valves. Good luck.


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## deerhide (Oct 20, 2016)

Dkat said:


> I have not done a compression check. Is that the best way to determine if the valves need adjusting?


A compression check (fairly simple to do)will tell you what the psi is in each(seperate) cylinder. Ambient air pressure(the air we breathe) is about 15psi I seem to remember. If your tractor has a compression ratio of, say 8:1, ideally the test gauge should show around 120psi. If you find you have a 'low' cylinder squirt a spoonful of ordinary motor oil the spark plug hole and test that cylinder again. If you have a normal, around 120, result then you have a piston ring problem, if you still have a low test you have a valve problem. These numbers are examples; look up the compression ratio for your engine.........the elevation level where you live affects these numbers too.


Ultradog said:


> You've had some good advice above. Always, always check your spark first. If you are satisfied you have good spark at each plug then go on to fuel.
> Remember that there are 3, sometimes 4 fuel filters on your tractor. First one is a screen on top of the shutoff valve at the bottom of the tank. Second one is a screen on the top of the fuel pump behind the radiator. Next one is in the sediment bowl behind the carburator. Last but not always is a scintered brass screen in the fitting where the fuel line goes into the carb.
> That is a good, reliable fuel system but it does need maintenance (cleaning) on occasion.
> That brings us to your Holley carburator.
> ...


You could have the best of a big blue spark but if it isn't at the right time.................


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## Dkat (Nov 28, 2019)

Hi all, thanks for the advice given 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. 

I plan to check the fuel filters next. 
Any ideas with this new info?


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## belchermw (Apr 4, 2017)

I bought a 67 that had a new distributor prior owner installed and had built carb too. He wanted to sell it and cut his losses and was gonna buy a new carb for it. I told him to hold on the carb and bought the tractor.

I cranked it with carb off and noticed air flowing “out” instead of sucking into intake. This meant valve issues, burnt, bent, or out of adjustment. I pulled valve cover and found 3 too tight and 1 too loose. I adjusted them all and this fixed the airflow problem.

I still had some missing and replaced 2 sets of plugs and 2 sets of wires over 1 year of messing with it. Set the timing to 4 degrees b4 tdc.

Finally I went to NAPA and got a set of Echlin points and condenser. Turns out the new condenser in the new distributor was shorted.

I also read all the comments and they are very informative. However I also pulled carb apart soaked it for 2 days, readjusted float. Now it starts within 1-2 sec in coldest weather and doesn’t miss.


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## XLENDI (Jul 22, 2019)

Might be worth checking. are you quite sure no cracks in the dist cab. Is the spring under the carbon rod in good condition.
Are you happy that when you set the points were in the correct position on the distributor cam.
The small pipe going into your vacuum advance, if you suck on this , can you suck or no, you should not be able to suck clearly, if you can the diaphragm could have a hole , this is you vacuum advance. as you increase engine speed this advances your timing.If you hold the rotor button when is fitted on the shaft do you have some movement. you have some advance weights and small springs , just check not seized. These two things advance your timing when you increase speed. When you test your plugs you want a nice blue spark , not orange or yellow. You can test with a screw drive when engine running and insulator of the plug, do not touch any metal unless you want an afro hair style. As coil is so close to the engine block , pls check top of coil for sparking , you can do this at night or in a dark place. It might not be a bad idea to change position of you coil, being directly under the carby , may get fuel on top of it. Cheers.


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## Dkat (Nov 28, 2019)

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?


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## Ed Williams (Jun 13, 2019)

Had the same problem with a F150 300 6 cyl. The acceleraton pump was just a piece of rubber on the acc side of carb. It looked fine initially, but eventually found a pin hole in the rubber by stretching it slightly. New one cured the problem. Worst part was I had to buy the complete rebuild kit, not the std kit, to get a new.one. that little piece of rubber cost $30. Not to be wasteful, I had a mech friend boil out the carb in his cleaner for 3 days, then installed the whole kit. Ran great after the OH. Mech cautioned me not to try to clean internal carb passages with small wire. They are precision machined and I would run the carb. A circulating cleaner/degreaser is the only option that won't cause any damage. He also said it takes days, not hours of cleaning to get all the gunk out of the carb internals. Good luck.


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## XLENDI (Jul 22, 2019)

Hi Dkat
did you get to the bottom of your problem , if yes would love to know what you have done to fix the problem. Cheers. Alex.


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## Dkat (Nov 28, 2019)

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.


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## XLENDI (Jul 22, 2019)

Did you check the vacuum advance. With what you are doing you will know your tractor inside out.
Cheers. Alex.


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## XLENDI (Jul 22, 2019)

Just had a thought , what does your fuel lift pump look like. Is it diaphragm type with arm that runs from cam.


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## Dkat (Nov 28, 2019)

I always appreciate when a poster updates the status of his issue so I am doing that here.

I worked through nearly every solution that was suggested to me. To summarize:
The tractor was running rough, missing out and backfiring through the carb. The problem started rather suddenly.

Here is the sequence of events (using the Shop Manual as a guide).....
I replaced the plugs gapped at .025
Installed new points and condenser, set the gap
Installed new plug wires
Pulled the distributor and checked and cleaned the flyweights
Found TDC on Compression Stroke and installed the distributor with rotor pointing to #1 and the points just beginning to open
Removed the Rocker Arm Cover and checked the valve tappets. Made minor adjustments to the valve clearances (.017 for intake and .021 for exhaust). Replaced the old gasket and re-installed the Rocker Arm Cover.
Replaced the Fuel Tank Shutoff Valve (old valve was broken but the filter looked ok)
Status: tractor still ran rough
Took off the Sediment Bowl; found that is was missing the internal filter and it had a small amount of rust colored sludge in it
Pulled the Carburetor and cleaned it thoroughly and installed a new kit; examined and cleaned the fuel inlet filter
Replaced the Sediment Bowl
Replaced a metal inline Fuel Filter
Adjusted the distributor timing by ear (will attempt to use a light to set it at 18 degrees BTDC soon)
Status: the tractor now fires up immediately and runs about 85% better

Issues:
Tractor misses out periodically, briefly at higher RPMs
Upon acceleration the engine stumbles and misses but recovers quickly; I suspect the new Acceleration Pump is not working fully
I also perceive hearing a "knock" from the valve tappets; but I can't tell

All in all, it is a lot better. I suspect the carburetor was the biggest problem.

I will ask this in a separate thread....but anyone have guidance on the Acceleration Piston Pump? The old one was terribly hard to get out (it was stuck fast in the carburetor housing. I filed the new one off a bit but it still seemed to go in with difficulty.

Comments and guidance welcome~


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## belchermw (Apr 4, 2017)

Timing is 2 degrees per manual 
Did u adjust valves with no psi on them and cold?



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## belchermw (Apr 4, 2017)

Here is a better pix 



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