Can't keep 9n ford running

J B

New User
This summer I was using my 9N ford tractor and it was running fine.I was plowing a garden spot when it just quit running and I couldn't get it running again. I took it and had the engine rebuild but that didn't help either. After I got the engine home and put back into the tractor and it ran rough and wouldn't stay running it would pop and snap and back fire. I took it apart and noticed that some of valves were sticking and the compression was 105 psi 90 110 and 90. So I took it apart to look at it and the cylinder walls wasn't honed that well. I took the pistons out and rehoned the cylinders to a nice crosshatch pattern. I took the valves out and cleaned and lapped the valves and put some new seals in. Checked the timing between the crank and cam. Bought a new distributor , carburator and plugs and wires. The timing is right and it's firing good. It still won't run without holding the chock out and it still won't run right.The compression checks between 120 and 125 psi on all cylinders. I thought the timing might be 180 out. So i cranked the engine over 180 degrees. It seem to run better but it was still back firing through the carb. Still getting the popping sound and still can't get it run right. I figured with the compression great and firing great it would at lease run right. But it doesen't. I am at wits end and help or sugestions.
 
Back fire is generally due to either of these:

1. Crossfire in cap, or wrong firing order. This on a front mount is quite often due to moisture, or simply because its easy to get wires mixed up. Firing order is 1-2-4-3. Distributor rotates clockwise (sitting in seat)
2. Lean air fuel mixture. Could be running lean due to diminished fuel flow, vacuum leak, or dirty carb.
3. Improper point gap - Check .015 on all four lobes.
4. Improper valve timing. While not real common for one to jump a timing gear it can happen. Your last compression test rules this out.
 
mvphoto7074.jpg


Offset tang on distributor drive prevents installing out of time.
 
First, just tossing new parts into the mix without performing a root cause problem solving method is wrong for any problem. Since you say it is a 9N we know then it has the front mount distributor. Did you rebuild the distributor correctly before installing? The offset tang mounts one way and that sets the timing once settings are right - point gap at .015". It is possible to turn unit 180? off but it will not bolt down flush and the moment you crank engine over it will bust the aluminum housing, no doubt about that. You can't change the timing like that, got it? Next, is it a 6-volt/positive ground original setup or do you have a 12-volt conversion? Electrical shorts can cause backfiring/popping sounds. The compression readings are good/adequate/sufficient -not the problem. Did you check for spark and fuel flow? Get a copy of Bruce(VA)'s 75 Tips for N-Owners and follow the tests for those systems. I suspect you may have a bad wiring issue combines with a bad fuel issue...report back with results and stop adding new parts. Pull off distributor and recheck it all on the bench. A new carb, new distributor out of the box is no guarantee their settings are right. What's wrong with old carb and distributor? They are easily rebuildable. If you need help send me your carb and distributor and I can rebuild them. Otherwise set carb mix screws to suggested starting points and leave them alone. Battery must be good, though not the problem of backfiring.

Tim Daley(MI)
 

My old 9N had been sitting about 2 years in a shed and when I needed to get it going again of course it needed some attention. Basically I followed Bruce VA's tests to check out the distributor and coil with a meter. Determined the coil was going bad and the points has resistance when closed and cleaning them didn't help... so new coil, new condenser and new points. Cleaned the plugs and checked all the wires over (years back had converted it to copper core wires). It had battery voltage to the coil so all good there. The carb had been recently cleaned, I swapped the one that was on it with one on my 8N and cleaned the 8N one (that was on this 9N originally) and reinstalled it and confirmed clean screens and good fuel flow. When all assembled again it fired right up.

Don't understand the statement about it didn't run so you took it to be rebuilt (?) Your choice of course, and it sounds like you got took good if the valve were sticking and the cylinders weren't honed right. Again your issue.

But as a cautionary tale to others DON'T DO WHAT THIS GUY DID! As Tim said, determine the cause of the problem before throwing parts (and $$) at it. Might have been something very simple, now this guy will never know since he's changed out everything.
 
(quoted from post at 14:10:35 12/04/17) " So i cranked the engine over 180 degrees. "

Please tell us exactly how you did that.

What i did was take the distributor out and crank the engine over to the same place it was but 1/2 turn. Then I put the distributor back in. If I am not mistaken it should be 180 out.
 
What i did was take the distributor out and crank the engine over to the same place it was but 1/2 turn. Then I put the distributor back in. If I am not mistaken it should be 180 out.
mvphoto7130.jpg


Unlike a side mount distributor, the front mount has an offset tang to prevent mechanical timing errors.
 
(quoted from post at 10:26:05 12/04/17) Back fire is generally due to either of these:

1. Crossfire in cap, or wrong firing order. This on a front mount is quite often due to moisture, or simply because its easy to get wires mixed up. Firing order is 1-2-4-3. Distributor rotates clockwise (sitting in seat)
2. Lean air fuel mixture. Could be running lean due to diminished fuel flow, vacuum leak, or dirty carb.
3. Improper point gap - Check .015 on all four lobes.
4. Improper valve timing. While not real common for one to jump a timing gear it can happen. Your last compression test rules this out.
Dollar Bill tonight I took the distributor out and tore it down and checked everything. Reset the points to .015, reset the plugs to .025 and made sure that gas was coming out the carb. Started it up and it was running for awhile but I had to keep choking it to keep it running it would run by it's self for a little while. Their was a lot black smoke coming out the exhaust. I tried adjusting the carburator while it was running and it wouldn't do nothing. I appricate all the help from you guys.
 
(quoted from post at 14:20:41 12/05/17)
(quoted from post at 14:10:35 12/04/17) " So i cranked the engine over 180 degrees. "

Please tell us exactly how you did that.

What i did was take the distributor out and crank the engine over to the same place it was but 1/2 turn. Then I put the distributor back in. If I am not mistaken it should be 180 out.
hat did nothing. You had to rotate the distributor by the same amount (90 degrees) in order to re-install it or else something would have broken when you bolted it down.
 
Started it up and it was running for awhile but I had to keep choking it to keep it running it would run by it's self for a little while. Their was a lot black smoke coming out the exhaust.

Sounds like you're making progress as you did not mention the back firing problem?

Black smoke could be self inflicted by over application of the choke or one of the following:
Leaky needle valve
Improper float level
Float is stuck
Unknown problem with new carburetor

If it were me, I would rebuild the original MS carburetor due to checkered reputation of repro carbs.

Set the side-pointing idle mix and the down-pointing main jet to 1-turn away from the seat as a starting point. These initial adjustment should get the tractor running unless there is an internal problem with your new carb.

When you get to the final carb adjustment stage, follow these procedures:

Once the engine is warm, move the throttle lever to idle. Set idle speed to 450 RPM, then try adjusting the IDLE MIXTURE screw. The correct procedure is to simply turn the [b:203f29ac1a]idle mixture [/b:203f29ac1a]screw in until the engine stumbles (too rich) then back out until the engine runs smoothly. Usually this increase idle above 450-500 RPM so you need to re-do the [b:203f29ac1a]idle mixture. [/b:203f29ac1a] When you get it right, the engine should accelerate smoothly, without smoke, as you advance the throttle lever from idle to full throttle.

If the tractor stumbles as you increase speed, then adjust the main jet. It will likely be happier enriched to 1-1/2 turns off of seat.
 
(quoted from post at 10:10:53 12/07/17)
Started it up and it was running for awhile but I had to keep choking it to keep it running it would run by it's self for a little while. Their was a lot black smoke coming out the exhaust.

Sounds like you're making progress as you did not mention the back firing problem?

Black smoke could be self inflicted by over application of the choke or one of the following:
Leaky needle valve
Improper float level
Float is stuck
Unknown problem with new carburetor

If it were me, I would rebuild the original MS carburetor due to checkered reputation of repro carbs.

Set the side-pointing idle mix and the down-pointing main jet to 1-turn away from the seat as a starting point. These initial adjustment should get the tractor running unless there is an internal problem with your new carb.

When you get to the final carb adjustment stage, follow these procedures:

Once the engine is warm, move the throttle lever to idle. Set idle speed to 450 RPM, then try adjusting the IDLE MIXTURE screw. The correct procedure is to simply turn the [b:8fd24b8566]idle mixture [/b:8fd24b8566]screw in until the engine stumbles (too rich) then back out until the engine runs smoothly. Usually this increase idle above 450-500 RPM so you need to re-do the [b:8fd24b8566]idle mixture. [/b:8fd24b8566] When you get it right, the engine should accelerate smoothly, without smoke, as you advance the throttle lever from idle to full throttle.

If the tractor stumbles as you increase speed, then adjust the main jet. It will likely be happier enriched to 1-1/2 turns off of seat.
Thanks Bill I am going to rebuild the carburator, it has to be in the carburator. W hen i do adjust the main screw and idle screw it don't seen to do anything. Still trying, hopefully i can get it figured out. Thank again.
 
When i do adjust the main screw and idle screw it don't seen to do anything. Still trying, hopefully i can get it figured out. Thank again.

No response to carb tweaks indicate a vacuum leak or dirty carb.

The most common mistake in rebuilding a carb is to soak it in cleaner then just blow it off with compressed air. You must run a wire through all of the tiny little passages. It takes very little crud to block a passage and the carb will never work properly.

Always happy to help - Post back if you need something.
 
I have a question Bill.
I lapped the seats and reset the valves. I left the manifold off and carburetor and I checked the compression. The compression would only come up to about 60 psi. You could see exhaust air or smoke come from the exhaust ports. Do you need the manifold on to check the compression.
 
The compression would only come up to about 60 psi. Do you need the manifold on to check the compression.

No. Both valves are closed on the compression stroke so the manifold has no bearing on compression readings.

60 PSI isn't abnormal for a newly rebuilt engine. Compression will come up after the rings have seated.
 
Sorry Bill I hate to keep bugging you, but this tractor is driving me crazy. I button it up put in spark plugs, antifreeze and oil but it wouldn't start. Took a compression check and it would pump to 50 psi on all 4 cylinders but when you stopped cranking it would drop back to zero. It wasn't holding the pressure. Why is this pressure jumping around one minute it'll check 120 to 125 on all cylinders, then it would check 145 on 2 cylinders and 2 cylinders nothing. This compression has been all over the place. I have tried starting fluid and nothing. Any advice

Thanks Jerry
 

Jerry, you're not bugging me - Very glad to help.

Erratic compression readings may be caused by two things. Faulty compression gauge or sticking valves.

Try another gauge for comparison.

Not sure of how you're doing the test so here's the steps that I follow:

Remove all 4 plugs.

Remove the breather hose & make sure the choke and throttle are both open.

Crank it at least 5 compression strokes or until the gauge stops moving.

Write down the first compression reading (that is the valve seating) then write down the reading after 5 strokes or when it stops increasing.

You should have two numbers for each cylinder. Then, add a tablespoon of oil to each cylinder & repeat the process, but you only need the final reading for each cylinder.

Number ONE: ___________ Valve Seating ___________ Second Reading ___________ With Oil


Number TWO: ___________ Valve Seating ___________ Second Reading ___________ With Oil


Number THREE: ___________ Valve Seating ___________ Second Reading ___________ With Oil


Number FOUR: ___________ Valve Seating ___________ Second Reading ___________ With Oil

Ford specs: 90psi min (dry) new 6:1 flathead engine is about 125psi.

[b:456bd203bb]Interpreting Results: [/b:456bd203bb]
+10psi increase good engine
+20psi increase normal engine
+30psi increase worn engine. NO INCREASE burned or stuck exhaust valve.
 

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