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1F engine running rough

Discussion in '40- & 55-Series Tech' started by sand rider, Mar 2, 2007.

  1. sand rider

    sand rider

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    well, i've running my 40 alot more than normal, lots of trail rides, new tires, lots of miles (like 400 miles).

    anyway, my engine has been running rather rough, partially cause of the drastic weather changes here in dallas. but its also putting out alot of soot from the exhaust. i've checked all the spark plug wires, and connections. (put spark plugs in 5k miles ago) i've tried to tune the carb, but i cant seem to figure out the right Air/Fuel.

    anyone A. know what the fractory settings are? and B. have any suggestions as to what i should check also?

    Thanks for the help

    Jonathan//SandRider

    oh, i found the engine number F 254279
     
    Last edited: Mar 2, 2007
  2. trekker

    trekker

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    Well that sucks! I'd love to help but you need to do a little homework first and provide a little more info...

    Yes... check your FSM. If you don't have a FSM --- get one. Bets $20 ever spent (other than getting a star here at mud). In a pinch, a Haynes manual will do. And ...Cruise the FAQ's here on mud as well as the search function.

    You will need to be a little more specific.

    Which carb?, What modifications have been made to the engine? These are "must know" facts before anyone can even begin to help out.

    Try this: https://forum.ih8mud.com/search.php?searchid=1629029
     
  3. sand rider

    sand rider

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    1968 fj40, made in feb-march (by frame number). has 1bbl aisan carb. nothing has been done to the engine except getting rid of the old air cleaner, and putting an aftermarket aircleaner on it.
     
  4. IDave

    IDave

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    I would pull the plugs and see if they show you oily, burned, carboned, fouled or normal, in one or more cylinders. Sometimes, they just get grimed up from fuel additives. Anyway, once you have that info you are better set to check other things. I would clean them and see what difference it makes, noting what you found before you clean them off.

    Then, it is easy to check the timing with a timing light. See that things are right there 7-10 degrees BTDC is usually good.

    A dwell meter is handy for checking the points gap (41 degrees is correct).

    Then, the usual starting point for the IDLE mixture (this is not the mixture you are driving around with, but what you can adjust with the screw) is: Screw in the screw all the way and then back it out 4 1/2 turns (you have to fiddle with the idle speed as well--ending up at 600-700rpm is good). Fine tuning the mixture is a matter of achieving maximum vacuum at idle (you need a vacuum gauge) minus an inch or two.
     
  5. 65swb45

    65swb45 Supporting Vendor

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    Check your points.
     
  6. sand rider

    sand rider

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    i pulled the plugs today, they were oily and carboned. cleaned them all up, put them back in and it sounds a bit better. but (as i forgot to mention before) my exhaust is pushing out alot of black soot/liquid and it sprays out pretty heavily. tomorrow im gonna check the timing.

    Jonathan//SandRider
     
  7. sepr2

    sepr2

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    I would do a compression check...
     
  8. IDave

    IDave

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    Oily plugs imply poor oil control. It might be as simple as a plugged PCV valve (easy to check, take off, see if it rattles when you shake, try cleaning it with solvent if it doesn't, or replace). Or, you may have worn rings and or valve guides. A bigger job to fix (see compression check above to help with that diagnosis). If you oil smells like gasoline, you may have a ruptured fuel pump diaphragm which can also give oily plugs. Hotter plugs might help temporarily.

    I'm not sure how you can tell you have carbon underneath the oil, but anyway, carboned plugs usually mean you're in need of a tuneup. Rich fuel mixture, stuck choke, clogged air filter, bad points, timing retarded, poor compression, cracked distributor cap...plugs too cold (are you using Densos?).
     
  9. sand rider

    sand rider

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    yes, im using denso's. w14's i think. pcv valve is right on the oil fill right? i'll check compression today also
     
  10. IDave

    IDave

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    PCV would be on the oil fill tube on a 68, right.
     
  11. sand rider

    sand rider

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    pulled the pcv valve out, and it wouldnt make a noise. cleaned it up and put it back in. when it started it sprayed oil for a bit, but stopped after driving it for a bit. im gonna start it up tomorrow to make sure its fixed.
     
  12. IDave

    IDave

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    Hows that? I mean, how is it spraying oil? It's supposed to have a hose leading to a fitting underneath the carb (the carb insulator, or plenum).

    And, yes, it should rattle when you shake it. Carb or brake cleaner sprayed into it might help.
     
  13. sand rider

    sand rider

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    the truck was spitting oil out the tail pipes. but since i cleaned the pcv valve, it stopped doing it. thanks for yalls help

    Jonathan//SandRider
     
  14. IDave

    IDave

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