not enough spark

uncle henry · Nov 18, 2012

everything has been replaced getting blue spark to
the plugs not enough to get it to fire spark plugs
are at .025 should i try .023 or go wider

CNKS · Nov 18, 2012

You have a problem elsewhere, your plugs are close enough.

Hattrick · Nov 18, 2012

It sounds like you either have bad plugs or that the plugs are not grounded good with your test.

FBH44 · Nov 18, 2012

I"m beginning to t hink gap doesn"t make much difference. Old guy at my CNH dealer toldme to run my "H" gap at 0.035 or so , tomake it a hotter spark. Seems to wkr.

David G · Nov 18, 2012

Why do you believe you do not have fire at the plugs?

John T · Nov 18, 2012

True, small gap changes dont make any night n day difference, but it can make some especially if things are already at the margin of operation.

When the coil conducts current theres x amount of finite energy stored. When the plug fires all that energy less heat losses gets dissipated across the arcing plug gap in the form of Volts X Amps X Time. If you widen the gap the voltage must rise, so EITHER the current or arc duration (or both) has to be less. You still discharge x energy but the voltage rises if the gap is increased while current is what usually decreases.

John T

John T · Nov 18, 2012

Changing the gap a few thousands isnt gonna make her run much different. If the spark is weak the usual suspects are points, condensor, plug wires, cap n rotor problems

John T

uncle henry · Nov 18, 2012

thanks i'll start pulling parts off my other tractor that runs to see what it is i need before i spend more money

Hattrick · Nov 18, 2012

Another thing that I have seen on cars is the coild can be installed backwards causing weak spark. Positive ground means negative to the coil positive from coil to distibutor. Negative ground would have positive to coil and negative from coil to distibutor. Easy enough to check just to make sure.

BOB HAWBECKER · Nov 18, 2012

if she fires on starting fluid then you got carb problems

uncle henry · Nov 18, 2012

i pulled the carb from a running tractor and put on this one because it was a aluminum carb i don't like them i'll try to work the bugs out this weekend thanks again

El Toro · Nov 18, 2012

Are you sure you're getting gas to the combustion chamber? Hold your hand over the throat of the carb and see if there's good suction. Poor suction means low intake manifold
vacuum. You could have a vacuum leak. Do a compression test too. Hal

BOB HAWBECKER · Nov 19, 2012

Uncle Henry how are you making out with tractor.
get it running yet?

not enough spark

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