Need help, can a new light switch install work cause no start?

Discussion in 'General IH Tech' started by Scout64, Aug 1, 2020 at 10:42 PM.


  1. Scout64

    Scout64 Farmall Cub

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    I have a 1964 Scout 80 with a 152, all original that has been sitting for a few years. Long story short, I finally have time to start on it and there is a big list of things to do. So far I have installed low pressure electric fuel pump, cleaned points, new condenser and put a bandaid on the 1904 Holley. It ran but was leaking fuel.
    Next day.
    Traced and troubleshot light wiring and all wiring is done for lights and everything works as it should but the headlight switch is glitchy.
    Next day.
    Carb was shot so I purchased and installed a new one and it started on the second crank. Idled and ran perfectly. Victory.
    Next day.
    Removed old light switch and installed a new one. Reinstalled light switch and starter key switch in dash. Late night and I did not start engine.
    Next day.
    I tried to start the Scout but no luck.
    Here is where I am on this.
    Will turn over but not run.
    I am sure compression is good ( was running)
    Electric fuel pump is getting fuel to carb
    Carb is squirting fuel into intake
    Spark is at plugs
    Removed and cleaned plugs
    Verified coil voltage
    Verified big resistor voltage
    Pulling remaining hair from my head

    Looking at the manual and wiring diagram I cannot see a relation to this problem just by installing a new light switch.
    Any help is greatly appreciated.
     
    Last edited: Aug 1, 2020 at 10:47 PM
  2. Don B

    Don B Binder Driver

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    I would check all the connections on what you put in for any that are loose. Also, check that the key switch connections are not loose in any way. Check that the spark
    at the plugs is good and bright. Most likely it’s something jiggled out of position/contact. My rant is also condensers and coils which are of poor quality and can fail at any time these days. I always swap these out if I’m stuck.

    Don B
     
  3. Scout64

    Scout64 Farmall Cub

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    Thanks for your suggestions. I didn't remove any wires from the key switch but it is tight quarters so something may have come loose. I will study the wiring diagram for that and I will go through and check again.
     
  4. Dana Strong

    Dana Strong Lives in an IH Dealership

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    Can you smell gas strongly at the tailpipe? Might the engine be flooded? If so, holding the gas pedal to the floor wile cranking will allow air but little fuel to enter, clearing the flooding in a short while.
    Is the spark at the plugs strong and blue? How are the wires? Might the spark be bleeding off due to poor insulation? The voltage needed to fire a plug under compression is greater than jumping a gap in open air.
    Any chance you fiddled with or bumped the distributor while working on things? I would check that the spark timing appears correct (and would assume it was correctly still on the firing stroke, if timed right). If you're getting a good spark when cranking, it should at least be able to fire a time or two, assuming air/fuel mix, timing, compression (including valve action) is correct.
     
  5. Scout64

    Scout64 Farmall Cub

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    Update: I rechecked the switches and re-seated the wires. I noticed that on the ignition switch I would turn the key it would push the back part of the contact away from the metal housing and then it would intermittently lose electrical contact, so there is a issue there.
    I don't know if that will resolve my issue but I have one on order along with a new ignition coil and will update when they are installed.
    There are a million other things to do in the meantime.
     
  6. Scout64

    Scout64 Farmall Cub

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    Update- I replaced my ignition switch and coil. Still no start. Will crank fine, has fuel reaching manifold, spark is ok......
    Running great, parked for 2-3 days while other minor work was done and then no go. I removed and recleaned points, condenser, plugs.
    Reviewed wiring and verified with wiring diagram.
    I did notice that if I crank for about 15 seconds I intermittently get a hit like it wants to start but it wont.
    I think my truck is a stubborn a$$...... now I know how my family feels. Thanks for any suggestions.
     
  7. TravelerMan79

    TravelerMan79 Farmall Cub

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    Not sure what it could be but gremlins exist. Pulled the alternator from one of our daily drivers because the pulley had seized and melted the serpentine belt. Got the pulley to spin freely after using my ratchet and then my air impact gun. Was spinning freely at thousands of rpm's. Two days later when I went to reinstall, the pulley was completely seized. Had to buy a new one. I'm guessing the new carb is the culprit.
     
  8. RinTX

    RinTX High Wheeler

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    Air - fuel - spark at the correct time. Seems to me you need to check everything associated with spark.
     
  9. Scout64

    Scout64 Farmall Cub

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    Getting spark but may not be hot enough. Is there a troubleshooting procedure to direct wire the coil to bypass the wiring to test run?
     
  10. 1975IH200

    1975IH200 Y-Block King

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    Ignition Coil testing......
     

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  11. Scout64

    Scout64 Farmall Cub

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    Thank you for the quick response and info.
     
  12. Robert Kenney

    Robert Kenney Binder Driver

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    So the only thing that changed between it running and now not running is the headlight switch?
    1) Ground the neg side of the coil (mimicking the points being closed). Quickly turn the ignition switch to run, recheck the + coil voltage. Don't leave the coil grounded and the switch on for very long, just long enough to check the voltage. If all things are good, you should see about 8 volts there. Reasoning, on the early the resistance wire goes straight to the switch and could have a high resistance at the connection with the switch.
    2) Verify the the starter solenoid boost wire, it connects 12 volts directly to the coil during cranking. While cranking verify 12 volts at the + coil terminal.

    If all of that checks out, and still no start exists, clean the points and or replace the condenser.
     
  13. mallen

    mallen Y-Block King

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    0) make sure the battery is fully charged. Never crank for more than about 20 seconds without giving it a minute to cool or you can kill your starter.

    1)do you have points or an electronic ignition? pull a plug wire, put an old plug on it, and sit it on something grounded away from fuel lines and the carburetor and the battery (which can create explosive hydrogen gas). You should have a nice strong spark. Check dwell with a dwell.meter whole cranking. Condensors are suspect, I hate the damn thing. They go intermittently bad or only fail under load. And they are difficult to test. Keep an extra known good around to swap in. Check the points for wear. But if your getting reasonable spark it should start. Even reasonable weak spark usually starts it unless there motors tired.

    2) just after trying to start it (NOT while its cranking but after or you could get a face full if fire) look down into the carburetor. Do you see dripping fuel? Do you smell raw fuel. Pull a spark plug. Is it wet with fuel. Do the throttle plates look wet. These are all signs of flooding , usually due to a stuck float or dirty needle valve.
    Operate the throttle either by hand using the linkage or by having a helper stomp the pedal. You should see two nice little streams of gas into the carburetor from the accelerator pump. If not the accelerator pump may be bad. Try spraying a squirt of starting fluid in the carb and see if it tries to start.
    Some possibilities are, stuck float allowing no fuel into the float bowl or stuck float, leaky float or crud in the needle valve allowing to much fuel into the float bowl which dumps into the engine flooding it, or bad accelerator pump not allowing that initial pump shot it needs to start or simply no fuel in the system so it needs the pump and float bowl primed.

    If you have no stream of fuel from the accelerator pump when the throttle is operators. Theres no fuel in the carb. If this is the case, it will try and start for a few seconds with a squirt of starter fluid or a few tsp of gasoline down the throttle bores. Dont pour gasoline in. It will get everywhere, you will get to much and you will probably start a fire.(trust me here, I speak from experience).

    If you have too much fuel, check the fuel filter for crud. Replace it. Add a second fuel filter with a very fine element after the first, finest you can get. Clean the needle valves. Adjust the float height. Prime the carb. And try again. Crud in the carb from a rusty fuel tank is probably the number one issue in these old trucks.
     
    Last edited: Aug 4, 2020 at 1:23 PM
  14. Scout64

    Scout64 Farmall Cub

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    Ok, update time.
    Don B- All connections are tight and wiring layout seems to match the wiring diagram. Points and condenser is cleaned and adjusted.

    Dana Strong- Getting fuel from carb, does not seem flooded but it does smell gas from tailpipe, spark is strong (old and new coil), cleaned points and condenser. Firing order is good. Verified strong spark and verified no leakage spark in dark.
    Sputters every once and awhile 1in 5 attempts to start.

    TravelerMan79- Gremlins DO exist and they is a nest of them in my Scout! May need to address the carb. It is a new carb but when I initially installed it cranked, ran, idled GREAT.

    RinTX- Spark seems good. May be timing tho.....
    (Sputters every once and awhile 1in 5 attempts to start.)

    1975IH200- Thank you for the info. I verified the wiring .

    RobertKennedy- I checked the voltages at the coil and here is the info
    At coil on acc 4v both sides of coil
    On acc 8-10v while cranking on both sid
    On ign 12.8v on both sides of coil
    There may be a discrepancy in there from what you were expecting?
    It seemed that there is a resistor wire and a big resistor. Just to verify, does the fuzzy insulated white resistor wire go on the ign portion of the key switch?
    I did NOT yet change the points and condenser but they are clean and not that old.

    mallen- The battery stays on a trickle charger all night and it's not old at all. Starter does get hot if it does not sit between starting attempts but cranks fine. It is a 152 with points and condenser. Yes, a Pertronix upgrade may be in order once I get it running again.
    New carb, ran fine for 2 days sat for a couple days to replace light switch and get lights going and then BAM no start. Doesn't seem flooded ( but could be) and it is getting a good single shot of fuel on each pump. (Sputters every once and awhile 1in 5 attempts to start.)
    First thing start attempt even tried no pedal ,slight choke and put fueling carb top.... still no start

    Whatever the solution will be, I'm certain that will be a simple fix.... it was running too good before it stopped.
    I want to thank everyone who chimed in on my issue. You are invaluable to the IH community and are in part why these vehicles are still on the road.
     
  15. Don B

    Don B Binder Driver

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    Maybe throw in a new or another condenser. I've had brand new ones go resulting in a poor spark. Another couple of things, cracked or poor cap, bad spark plug wires. One fairly common thing (at least for me) is wires that look ok but are actually broken inside the wire sheath. You can tell this by them usually being loose feeling where they are normally wired or plugged in. A multimeter sometimes doesn't work as they happen to sag just right and make a connection. I've had this wicked scenario happen to me more than once. Also, never a bad idea to disconnect the fuel line at both ends and blow it out in case you have water sitting at the low point. Again, I speak from personal experience on this.

    Cheers,

    Don B
     
  16. Dana Strong

    Dana Strong Lives in an IH Dealership

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    Have you checked the timing yet? I'd suggest removing the high voltage wire from the top of the coil, removing (and cleaning) the spark plugs, spinning the engine with the starter to blow any excess fuel from the cylinders and checking the timing, too. If you think the carburetor could have water in it, also remove it and dump the contents into a pan to check for water. Then reinstall the carb, replace plugs, perhaps prime with a tablespoon-worth of fuel, and try starting again.

    I second the comment above about plug wires; as I said earlier, "Is the spark at the plugs strong and blue? How are the wires? Might the spark be bleeding off due to poor insulation? The voltage needed to fire a plug under compression is greater than jumping a gap in open air.", this last part meaning that high resistance in the wire core might allow a spark when testing on the side of the engine but not on an installed plug during a compression stroke.
     
    Last edited: Aug 5, 2020 at 11:23 AM
  17. mallen

    mallen Y-Block King

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    Start at the beginning. Check compression. Make sure that not only do you have spark at the coil you have it at the plugs. The more you check the more its looking like its not electrical. So try and start it again, then pull the plugs and see if they are wet. (One at a time) This smells of a carb problem... Pun intended. Good answer btw of going pertronix AFTER you get this problem fixed. Changing things, messing with the timing , pulling ALL of the plugs at the same time and risking confusion over the firing g order, etc would just make it harder.

    On the ignition side of thimgs, try this. Hook up a timing light. Have a friend crank it and see if you can read whether the timing looks right.

    On the fuel side, inspect your choke.
     
  18. Robert Kenney

    Robert Kenney Binder Driver

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    So the only relevant voltage to check is from the + coil terminal to ground. Under my previously described conditions the voltages should be as I I stated. Any other conditions don't properly test for the issue I suspect..\\

    Yes the white fuzzy resistor wire goes to the IGN terminal of the key switch. You might verify the switch is supplying 12 volts to the IGN terminal while the key is in the run position and while cranking.
     
  19. Scout64

    Scout64 Farmall Cub

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    Roger that. The switch voltages are verified at the coil in start and ign. positions. Why would there be 4v while on acc?
     

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