9N Electrical Starting Problem

Jo Bird · Mar 11, 2018

I've worked 2 days on this thing and cannot wrap my mind on whats going on, so I've triple checked every thing. Here is what I found ..
Tractor has been converted with a kit to one wire alt., 12 V ,neg. ground, with ceramic resistor in line to front mounted square coil. Not sure whether it is a 12V or 6V coil. but that should not matter.
Did a " tune up ", new plugs, points, cap/ rotor. Tractor did run before, tractor turns over fine, with points opening and closing, but wont start up. If I put a jumper wire from battery to the coil it fires up in one revolution. Remove wire after it starts and it continues to run.
The battery is 12.7 static charge, 14.7 charge rate from alt. while running and shows below CCA according to battery tester. Hence I added battery boost to the equation and still didn't make and difference. So, will a new battery solve this or have I missed something simple ?? What the heck is going on ??

Bruce (VA) · Mar 11, 2018

" with ceramic resistor in line to front mounted square coil."

" If I put a jumper wire from battery to the coil it fires up "

Don't you see the relationship here?

HINT: see tip # 30.
75 Tips

JMOR · Mar 11, 2018

As Bruce is saying (sort of) you have insufficient coil primary current. Ceramic resistor is very likely too large a value.

rvirgil_KS · Mar 11, 2018

?Not sure whether it is a 12V or 6V coil. but that should not matter.?

It definitely does matter. Bruce covers that discussion.

?Tractor has been converted with a kit to one wire alt., 12 V ,neg. ground, with ceramic resistor in line to front mounted square coil.?

Assume you mean added resistor that came with conversion kit. That resistor should be a max of about 1 1/2 ohms. I?ve seen some kits that came with a resistor of up to 6 ohms. Too much resistance gives weak spark, hence hard starting and poor running.

JMOR · Mar 11, 2018

(quoted from post at 12:33:15 03/11/18) ?Not sure whether it is a 12V or 6V coil. but that should not matter.?

It definitely does matter. Bruce covers that discussion.

?Tractor has been converted with a kit to one wire alt., 12 V ,neg. ground, with ceramic resistor in line to front mounted square coil.?

Assume you mean added resistor that came with conversion kit. That resistor should be a max of about 1 1/2 ohms. I?ve seen some kits that came with a resistor of up to 6 ohms. Too much resistance gives weak spark, hence hard starting and poor running.

es, that is what I said, insufficient primary coil current.

HCooke · Mar 11, 2018

Jump around the ceramic resistor and see what happens.

mhb@ufe · Mar 11, 2018

The kits always seem to come with a 12 volt coil and the resistor which doesn't make sense because you don't add the resistor when you use the 12 volt coil. As others have said it does make a difference which coil you have.

Mark

Jo Bird · Mar 11, 2018

Thank you all for trying to help, this thing is finally running again. I missed something simple. After checking as you all referred to , the resistor ohms out correctly for the 6 volt coil. The simple over looked thing was a crack on the bottom of the coil shell. Thanks again.
Jo

9N Electrical Starting Problem

Jo Bird

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Bruce (VA)

Well-known Member

JMOR

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rvirgil_KS

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JMOR

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HCooke

Well-known Member

mhb@ufe

Well-known Member

Jo Bird

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