200 Coil Question

When I rebuilt the motor on my 200 I did not replace the coil or distributor which was the original 6-volt system and both are probably original. The tractor ran fine and cranked easily on the old ignition . . . until recently. I parked it about 2-3 months ago and have been too busy to get back to it. Now it will not crank or even sputter. It has gasoline in the cylinder and will not fire on starter fluid. With the switch on there is fire to the input side of the coil. The only change I have noticed was that the amp meter no longer moves when the switch is turned on or off. I suspect the coil has gone bad. What do you think?

> Now it will not crank...

A bad coil will not prevent it from cranking. Check the battery, connections, and cables (both ends of both cables).

"The only change I have noticed was that the amp meter no longer moves when the switch is turned on or off."

With the switch on IFFFFFFFFF the points are closed (as they usually are when shes just setting there) and IFFFFFFFFFFFF the points aren't badly burned or pitted or corroded and IFFFFFFFFFFF all the wires are in place like from coil to distributor to points and IFFFFFFFFFFFFFFFFFF the coils LV Primary is good and continuous (NOT open) YEP NOT RUNNING SHE OUGHT TO SHOW A 4 AMP OR SO - DISCHARGE.

Put a test lamp or voltmeter on the coils output (To distributor) terminal and turn IGN on. When a good set of points are closed the light should be OFF but when they open it should be ON (if coil LV primary is okay).

If theres voltage on the coils input but not on output (unhook output wire completely from distributor) the coils LV primary must be bad/open.

Or else use an ohm meter and measure resistance from + to - and it should be maybe 1.2 to 2 ohms BUT IF ITS AN OPEN CIRCUIT THE COILS LV PRIMARY IS BAD/OPEN


I suspect the coil has gone bad. What do you think? SEE THE ABOVE

For a complete coil ignition test procedure see my link below

John T
John Ts Ignition Troubleshooting

To be sure what you mean, I reply: The cranking of an engine is either by an actual hand crank, or the spinning of the engine using the starter motor. Cranking is turning it so it will start. Firing, running, sputtering and backfiring all can happen while cranking. With respect, Jim

I am not sure where LMack is from, but around northwest North Carolina a lot of folks use 'crank' and 'start' interchangeably. e.g.: "Git in there and crank it up, Earl"

Janicholson: I always appreciate your replies, they are well reasoned, factual and seem to be spot on. Always good info. and a lot of help.

Garry

Clean the points. A coil doesn't go bad while sitting, but the points will corrode & not make contact.

Like teddy52 says clean the points easy for them to get a film setting around thats the first thing coils dont go bad setting around clean the points and see it then there is fire there.

John t if the points have a film they will not have contac and no discharge on the meter BTDT

That's right, a light gray oxide coating or oily film or carbon or pitting or burning or anything else that is a non conductor or too much resistance hinders current flow therefore no or low ammeter readings.

John T

(quoted from post at 18:09:22 11/20/13) I am not sure where LMack is from, but around northwest North Carolina a lot of folks use 'crank' and 'start' interchangeably. e.g.: "Git in there and crank it up, Earl"

Click to expand...

Technically, "crank" is still the act of driving the engine's moving parts with the starter motor, or a hand crank in that context. "Start" is the IMPLIED desired result.

"Crank" and "turn over" are often (incorrectly) used interchangeably with "start." That works in a non-technical context, where people know what you mean.

We're working in a VERY technical context here, so you need to be CRYSTAL CLEAR in what you mean so that everyone is speaking the same language and can offer useful help.

It does no good to clean the points or check for voltage at the coil, if the engine doesn't crank/turn over with the starter.

It does no good to charge the battery and clean the cable connections if the engine is cranking just fine, but will not START.

Someone who hasn't learned this stuff yet will not understand that one has nothing to do with the other, and will waste hours tinkering with the ignition when they really need to clean the battery cables or look at the starter motor itself, or vice versa.

Thanks Guys with a special thanks to John T. BTW John, should there not be a dip in the amp meter when the ignition switch is turned on. It always has for any coil ignition system I have ever used. I still suspect the coil because there is no movement in the built in amp meter with a full 6-volts to the input side of the coil. If there was a short inside the distributor cap or with the through bolt then a dip should show in the amp meter. You guys have given me a lot to use. This coil may be about 60 years old and I think it might go bad just sitting up in a shed. I will let you know what I find. Thanks again and I am located just south of the ATL airport.

"BTW John, should there not be a dip in the amp meter when the ignition switch is turned on. "

YES INDEED THERE SHOULD BE and around 4 amps as I posted below IFFFFFFFFFFFFF all the correct conditions are met and in place and working as I described...

"I still suspect the coil because there is no movement in the built in amp meter with a full 6-volts to the input side of the coil."

HOWEVER even if the coil is good theres still no ammeter movement UNLESS the points are good and closed and NOT burned, pitted or carboned or oil or oxide coated!!!!!!!!!!!! Take the coils output (To distributor) terminal and dead ground it then see if the ammeter swings to - discharge when IGN is turned on??? That eliminates and by passes all my described conditions.

Place an ohm meter on the coils LV + and - Primary terminals. If it reads around 1.2 to 2 ohms the coils LV primary is intact, if it reads an OPEN circuit the coils LV Primary is bad/open.

Put a 6/12 test lamp on the coils input and with IGN on it should glow, place it on the output (to dist) and it should glow when points are open (UNLESS LV coil primary is bad/open) but go off when closed (Unless burned or pitted or coated or not fully closed)

Id suspect the points or condensor BEFORE THE COIL

HOWEVER the 2 or 3 tests I described above are so quick n easy to see if the coil is bad/open!!! And it may well be, get a test lamp and ohm meter out to find out if its open?????

Best wishes n good luck, let us know

John T

With all terminals removed testing the primary lugs yields an open circuit. The secondary yields a little over 5 ohms. I will replace the coil and get back to you. Thanks. (The condenser, points, distributor cap, rotary button, wires, etc. were all recently replaced with new stuff so with that inside information I suspected the coil which had not been replaced.)

You're getting there.......YES If theres no circuit/continuity (I.E. an open circuit) across the coils small LV Primary terminals (+ and -) THE COIL IS BADDDDDDDDDDDDDDD It ought to be 1 to 2 ohms or so if its a 6 volt coil certainly NOT open

John T