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Subject: 8n issues (6V, front mounted distributor)

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Tony    Posted 05-16-2020 at 08:27:56 [URL] [DELETE]        [Reply] [Email]  
  • 8n issues (6V, front mounted distributor)
  • Hello, everyone, we got our 8N running, and have used it a couple of times to cut grass. Overall, it seems to run well, but we have some concerns.
    1) Runs and pulls well while cutting grass, then aftert about an hour it sputters to a stop. No apparent issues with fuel level or overheating. After about 15 minutes, it fires up and continues working.
    2) In order to start, we need to use the starter and the hand crank to get enough crankshaft velocity to fire. Meter shows 6.4 volts at the battery with no load, and we make sure it is on trickle charge while not in use. Stronger battery? 12 volt conversion?
    3) In order to start, we use a "jumper" between the coil and the battery for full voltage to the coil, then remove it upon firing. Voltage at the coil is about 4.5 post-ballast resistor. We were thinking of installing a permanent circuit to do this, with a toggle switch. Comments?
    4) The tractor requires full throttle to cut the grass with a Woods RM600 mower deck (rebuilt); is this normal?
    5) Can anyone recommend an aftermarket tachometer and water temp gauge for the 8N?

    Thanks in advance for any answers, suggestions or solutions.

    Tony    Posted 05-21-2020 at 17:09:40 [URL] [DELETE]        [Reply] [Email]  
  • Re: 8n issues (6V, front mounted distributor)
  • Update: We decided to tune the carburetor running mixture, idle speed, idle mixture. The 8N now idles smoothly at the bottom of the throttle quadrant, accelerates smoothly, and we can cut grass in 2nd gear at 2/3 to 3/4 throttle. Huge difference in the way the engine sounds and pulls.

    Our next project is the hydraulic system. Left drive axel (from driver's seat) is definitely leaking fluid from the center (seal?). Also the hydraulics operate, but the lift does not stay lifted, it slowly looses height. The fluid is at the proper level as shown by the dip stick. It appears to be light tan in color, is this normal?

    Tony    Posted 05-18-2020 at 08:17:23 [URL] [DELETE]        [Reply] [Email]  
  • Re: 8n issues (6V, front mounted distributor)
  • Thank you, everyone, for your thoughts and recommendations.

    I just cut the grass again yesterday and confirmed that the tractor does seem to bog down in spots with heavy grass and/or when climbing a hill. It ran for about 75 minutes and did not sputter or die this time. As before, I needed full throttle in 1st gear to get the job done. I tried 2nd gear on a flat area, and while the tractor was moving slightly faster, the engine was definitely working much harder at lower RPM.

    Since we have very little information about how it was maintained over the past 70+ years, here's what we have done over the past few months to try to improve the starting and running of this tractor:
    * Followed Bruce's recommended starting sequence & procedure
    * Checked circuits with a meter, and compared the values to what is in Bruce's list of 75 tips
    * Bought shop & user manuals
    * Replaced the starter with a new one when the original had stopped turning altogether (kept the old one for rebuilding as a spare)
    * Replaced the starter switch with anew one
    * Replaced the Zenith carb with a new one of Marvel-Schebler design, along with a new inlet screen; The Zenith did not look like anything we had seen in any 8n reference pictures, and had additional adjustment screws for which we did not find any adjustment information; initial settings on the new carb per recommendations from Bruce (kept the Zenith for rebuilding as a spare)
    * A few weeks ago, we noticed liquid bubbling out of the center head bolt between spark plugs #3 and #4. We pulled the cylinder head, replaced the bad head gasket with a new metal one, cleaned the block, pistons and the visible surfaces of the valves; had the head tank-cleaned and honed .010 by a local shop, reinstalled head with torque wrench to factory specs in the correct order; copper-core spark plugs cleaned and reinstalled with correct gap, non-resistor plug wires reinstalled correctly
    * Cooling system drained, replaced with water and coolant flush, will drain and replace with proper coolant after running additional hours; presently no thermostat, but we have a new one to be installed after the coolant flush is complete
    * Oil & filter changed
    * Removed and cleaned the front-mounted distributor, installed new points and condenser, points gapped to .015 as per spec, all new gaskets

    Here's our plan:
    * The battery cables will be replaced with #1 gauge, since good cables are critical to getting the most efficient use of the 6V battery
    * Have the battery tested under load and replaced if needed
    * We were thinking about a tachometer in order to see what RPM range at which the tractor is actually running. For example, if the red line is 2,200 RPM at WOT and IF we are only getting 1600 when mowing flat ground, we need to find out why (allowing for parasitic drain from mower deck); what is the acceptable RPM range while mowing?
    * Compression test, compare to factory spec and consistency between cylinders
    * Check the screens in the glass fuel bowl and replace if necessary
    * Check the point gap again to ensure it is correct
    * Fine tune the carb idle mixture and non-idle mixture
    * Follow recommendations made in this string of the forum
    * Run through all of Bruce's 75 tips again

    One other issue, relatively minor, the throttle lever will not stay in one position, it wants to go back to idle unless I hold it while running. While this is good for an automobile, it's a pain while mowing. We cleaned the little detentes on the quadrant, as previous paint jobs had filled in the crevices. No improvement. Any ideas?


    Mike W    Posted 05-18-2020 at 21:01:39 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 8n issues (6V, front mounted distributor)
  • I would be interested to see how the governor reacts to the engine being placed under load. It should open the throttle smoothly and steadily to compensate for the need for additional power.
    I worked on one where the throttle wouldn't stay where it was supposed to. The spring at the base of the throttle shaft needed to be repositioned on its mounting brackets. Doesn't seem like there's much difference one way or another, but it was the answer.

    Jack - Iowa    Posted 05-16-2020 at 22:18:02 [URL] [DELETE]        [Reply] [Email]  
  • Re: 8n issues (6V, front mounted distributor)
  • Starters of that vintage used a bushing in the rear. Those had a habit of wearing out and letting the armature drag. Takes a LOT of power to turn a dragging armature. At that time you could buy a new backing plate with brushes installed. Made for an easy repair but they are no longer available as far as I know.

    On a 2N and I suspect the 8N also, you can hold a quarter across the terminals of the ballast resistor instead of installing a jumper.

    The tractor was designed for 6 volts. Fix the problem and you won't have to go to the expense of converting it.

    The very late 8N's came with a tachometer. You would either have to make a hanger or get a dash panel from a late 8N. I don't know where they connected the cable. If you can locate a electronic tach it would be easier to connect.

    Mike Wilson    Posted 05-16-2020 at 18:38:36 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 8n issues (6V, front mounted distributor)
  • A weak 6 volt battery can crank an engine seemingly as normal but not have enough capacity to create the necessary spark. Load testing the battery will disclose whether this is the issue. As they say, clean and tighten all the battery connections. It only takes a very little resistance to mimic a weak battery. If it does hot and is a non- spark condition at that point, probably coil related.

    Mike W    Posted 05-16-2020 at 18:59:20 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 8n issues (6V, front mounted distributor)
  • Also be sure you're using adequate battery cables. 6 volts require heavy one or two gauge cables. Often find nice new 12 volt cables on a difficult to start 6 volt tractor.

    John in Mich    Posted 05-16-2020 at 14:59:28 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 8n issues (6V, front mounted distributor)
  • First, do what Tim said below. Out of 26 Ford Ns that I have owned, only one is 12 volt as purchased. The previous owner installed a fender mount radio, 12v lighting and a 12v winch on the front bumper. It also has electronic ignition. He did a nice job and I'm leaving it that way.
    That said, all others currently in my collection are 6v. IF they don't start or don't run, fix what is broke. Do NOT throw parts at it. As Tim said, proper diagnosis, 75 tips listed on this site.
    Lastly, both my son and I have HAD RM600 mowers. Both worked very well. At first I used it behind an 8N, 3rd gear. My "lawn" is not a golf course. It is an old farm field that I mow to look like a "lawn". It has bunches of weeds. We are finishing our first dandylion growth. LOL My 8N has a strong engine.
    Then, I used it behind my NAA Jubilee and my son also has a Jubilee. Good working tractors! Again, 3rd gear. There were times I might do some taller weeds and drop down to 2nd and even 1st and maybe even lift the mower slightly on a first pass.
    Notice I said HAD RM600s. Now, Gravely zero turns do the mowing. Actually quicker than the Woods because I do no trimming. I use Roundup. If a zero turn can't reach it, Roundup can.
    ps Son's tractor is in my garage right now. We have installed a transmision with a Hupp combination transmission and we have rebuilt the whole front axle. We have installed a drive for a loader that we are mounting. Hopefully, the loader will get mounted next week.

    Tim Daley(MI)    Posted 05-16-2020 at 10:01:54 [URL] [DELETE]        [Reply] [No Email]  
  • Re: 8n issues (6V, front mounted distributor)
  • First, welcome aboard. Do you have the Essential Manuals? No? Invest in them. They are every bit as important as any wrench. #1 –Suspect a fuel issue, read more below. #2 -No, you don’t need 12V, why do you think that? Are you running an 8-Track Player? 6V works and runs fine, has for 100 years. 12V has its merits but I’ve never found a reason to convert. #3 – using a 12V battery source to jump with? Whatever, not doing it right. You can jump start a 6V by connecting to starter post then touching to ground see 75 Tips. No need to add any useless whistles and bells to the ‘circuit’. Do this: Set your VOM to DC VOLTS, place one probe on LH terminal post of ballast resistor, the single wire goes to the top of coil. Place other probe to metal ground. KEY ON but do not turn engine over. Reading should be battery voltage with points open, half that with points closed. #4 – A WOODS 600 mower is fine. ¾ Throttle is normal. Open full can mean loss of power due to worn engine. Mow in 2nd gear. #5 –there are aftermarket tachs and temp gauges but not really needed in my opinion. Many were and still are used without them. Save you money and spend on PM.

    FUEL, SPARK, COMPRESSION are needed to run. First, check battery on a bench test machine, not simply charging. A starter shop or auto parts store will do it for free. A 6V battery does not mean it is wired correctly. From our HOW-TO’s forum, get the manuals and JMOR's WIRING PICTOGRAMS and verify wiring is correct. Check for spark per Bruce(VA)'s 75 Tips. Next, check fuel flow. One system at a time and do not start pulling off parts and replacing. Perform a true root cause problem solving method to determine if a part is defective. Spark test first before fuel test. You don't want any spilled gas around when you test for spark. Test for battery efficiency first. Pass? Move on. Fail? Get tested and replaced if defective. Next step is to spark test. Pass? Move on. Fail? Use a VOM to test wiring via continuity to coil and distributor. None? It's in the distributor. Next step, fuel flow test. Pass? You should be good. Fail? Fuel system needs troubleshooting from tank and sediment bulb to carb –see below.
    Probable NO-GO fuel issue causes are: plugged vent, plugged screens, plugged sediment bulb, dirty gas tank, dirty carb, and more. There are three OEM screens in the fuel system. Two are on the Sediment Bulb Assembly; the 3rd is on the brass elbow inside the carb where the fuel line connects to. SEE PICTURES. I wouldn’t be shoving anything, wires especially, up into the sediment bulb assembly. You have a vertical fine mesh screen on the inlet port inside the tank that you can damage. Best solution is to remove the tank and thoroughly clean.


    PRIOR TO S/N 8N-263844:

    A float charger is needed, NOT a trickle charger, but a float charger, like the DELTRAN Battery Tender Jr. ® ™ . A battery charger, even a "trickle" charger, left unattended will eventually boil out a battery. Use a float charger for two reasons: battery longevity and a sure start. Battery sulfation occurs at a specific rate at "X" temperature. Over time, sulfation reduces battery performance and eventually its effects are irreversible. Sulfation of batteries starts when specific gravity falls below 1.225 or voltage measures less than 12.4 for a 12v battery, or 6.2 for a 6 volt battery. Sulfation hardens on the battery plates reducing and eventually destroying the ability of the battery to generate current. Using a float charger significantly reduces sulfation. Your battery loses 33 percent of its power when the temperature dips below freezing, and over 50 percent of its power when the temperature falls below zero. A fully charged battery will not freeze until -76°F; however, a fully discharged battery can start to freeze at 32°F. So……keep the battery fully charged! If you have a digital volt meter, 6.03 volts on a 6 volt battery and 12.06 volts on a 12 volt battery is only a 25% charge!



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