400 having troubles...

Kawookie · Feb 24, 2020

I am currently working on resurrecting a 400 farmall.. it had sat in shed for a few years before I purchased.. I cant get to start.. I can get smoke mostly white but a little black and sounds like it wants to run with starter turning but doesnt.... and manifold does get warm... I have cleaned the carb but not sure I have set right . Put in fresh fuel, new starter, new plugs, points, distributer cap, coil.. questions... I am on a 12 v system and coil says 6 v without external resister.. so I dont know if it is correct.. other question involves timing.. so I set top of center as in my operator manual and then I try and start a few times and checked again but now distributer pointer at 3rd spot instead of 1st spot... ( so directly opposite to where it should be
. I have also put new belts on... any help would be appreciated before I have to call my mechanic buddy and look silly... thanks in advance..

Bob · Feb 24, 2020

It makes no difference as to the position of the distributor, as long as the #1 wire is in the correct place and the others follow in firing order.

If the points are JUST opening as #1 comes up to TDC at the end of the compression stroke, timing should be close enough to start and run. OBVIOUSLY, the rotor needs to be pointing to the high-tension terminal connected to #1 sparkplug at that time.

It's POSSIBLE you have it timed 180? distributor degrees "off" and it's sparking at the end of the #1 exhaust stroke, rather than at the end of the compression stroke.

As to the coil, the way I interpret your post, it is a coil intended for use on 6 Volts with no resistor, an external resistor WILL be needed for 12 Volt operation.

leemn · Feb 24, 2020

grab rotor and try to turn to make sure pin hasn't sheared on dist drive

jhncp · Feb 25, 2020

Are you sure you are checking rotor on correct stroke? The crankshaft rotates twice for one revolution of rotor. You can squirt ether or gas into spark plugs holes and if it don't even pop you got ignition timing problem or no spark. You can just have coil wire coming out of coil a quarter inch away from ground instead of in dist cap and should easily arc as you crank over.

used red MN · Feb 25, 2020

Pull all the spark plugs, then you need a helper to either turn the engine or hold their front finger or thumb in the number 1 spark plug hole just enough to loosely seal it. Not sticking it in so it can get smashed. Hopefully you know the cylinder by the fan is number one. If the belt slips while trying to turn it tension the lose side with your free hand. When air is felt pushing out of no. one plug hole continue to turn until the pointer on the front pulley passes one mark and lines up with the second. The rotor in the distributor should now point to the cap terminal to the number one spark plug. If that is correct your timing should be close enough to start it. Check your spark as jhncp has recommended.

used red MN · Feb 25, 2020

Also Bob is correct about the 6v. coil needing a resistor, however that is not keeping your engine from starting. The tractor will run on 12 volts fine. Long term running without the resistor will over heat the coil and burn points quickly.

Dave BN · Feb 25, 2020

Yep, sounds like timing is 180 degrees off. As others have said you need to set timing with #1 cylinder on compression stroke.

Dave

rustred · Feb 25, 2020

so it sounds like here you created a problem that was not with the tractor. it must have been driven in the shed under its own power. don't know why you started replacing parts before starting it. guys saying 180 degrees off? well don't see how if you did not pull distributer. so.. it maybe you have the wires on incorrectly. have you checked that? get #1 cyl. on compression at TDC with timing marks lined up. then look where the rotor is pointing. from factory it will be in the 2 oclock position. firing order is 1342 clockwise. as for the carb you don't know if its set right?? turn out main jet on bottom 2 1/2 to 3 turns out. turn the mixture screw out 3/4 turn , it will run pretty darn good at this setting. fine tune after your points and timing is set, not before! and yes you will have 2 TDC's for each cyl. so make sure you are on the compression stroke at top dead centre. so did you pull distributor or not? did you check the carb screw settings before removing them? or did you even remove them. lots your not telling. every little detail means something.

Kawookie · Feb 25, 2020

Thanks for the help.. i am a young fella with not a lot of mechanical experience and this is the first old tractor I have worked on. I have really enjoyed tinkering.. wiring lights all up now too... to be honest yes I did Have distributor off because gasket was torn and I was careful to take apart and put back in the same place so I thought.. I have taken a couple nights off from it but hope to try it again tommorow night after work.. really thinking it is timing as I do have good spark and will hook to external resister.. just think I need to make sure compression happens af the same notch I have been setting to.. thanks again and I will be back I am sure

BarnyardEngineering · Feb 26, 2020

The coil will work for a while on 12V without a resistor as long as you limit how long the ignition is turned on and allow it to cool.

This will also give you the hottest spark which will give you the best chance of the tractor starting.

rustred · Feb 26, 2020

a tid bit... put yourself a mark on lower distributor where it meets housing with a tiny tiny punch make two punch marks to line up, or even just scrib a line on both. then remove the cap and put a mark on the distributor housing where the rotor is pointing. then u can pull out the distributor, and do what u need to and then just stuff it back in and get the rotor lined back up then line up the housing marks u made and start it up. simple easy. to fine tune it u can check you timing with a light anytime. then do the carb adusting once timing is set. I don't trust any timing settings till I visually see where it is at. meaning the last guy could have timed by ear and that wont do.

400 having troubles...

Kawookie

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Bob

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leemn

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jhncp

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used red MN

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used red MN

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Dave BN

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rustred

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Kawookie

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BarnyardEngineering

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rustred

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