Electrical starting problem

merbeau

Member
I have a Harry Ferguson T0 30 tractor that has been converted to 12 volt operating system replacing the magneto.

The tractor would not start so I took off the distributor cap and the points were really burned. I replaced the old points, condenser, and rotor. Tried to start the tractor and nothing.

When I remove the distributor cap and try to start the engine there is no spark at the points.

I checked the spring on the back of the resistor and it is intact.

Can this be the coil? or voltage regulator? If the coil then do I purchase one without an internal resistor.

thanks

robert
 
Voltage regulator has NOTHING to do with the ignition system.

Grab a 12 Volt unpowered test light and check for power at the distributor primary terminal with the ignition switch "ON".

With points "open" test light should light, and go out when points are closed.

Check that and post back.
 
(quoted from post at 17:20:59 03/31/18) Voltage regulator has NOTHING to do with the ignition system.

Grab a 12 Volt unpowered test light and check for power at the distributor primary terminal with the ignition switch "ON".

With points "open" test light should light, and go out when points are closed.

Check that and post back.

Thank you for replying

Took me awhile to find my voltmeter. Tried at the points at reading was zero, then turned on switch and it read 12 volts. Then turned off switch and read at the coil and it was zero. Turned switch on it was zero. Went to battery and it was 12 volts. Then tried switch and it was zero. Turned switch on and it was zero. Wiggled switch and it read 12. Then tried coil and 12 and points 12. Turned switch off and on and it read zero.

Perhaps it is a bad switch?

Thanks

Robert
 
Bob, I see one possibility where a generator voltage regulator could affect the ignition system. If the ignition switch was powered from the L terminal of a 4 terminal regulator and the L path were open it would kill power to the ignition switch. I would expect that to be a very rare occurrance, but still a possibility.

Otherwise, as you say, the regulator has nothing to do with ignition
 

Ok, went to store today and purchased a new switch. Came home and hooked it up. When the switch is 'on' and placing one lead from the coil and then other to the points the reading is 12 volts. When the switch is turned off the reading is zero.

Tried to crank the tractor and nothing. Took the distributor off and the rotor and cap. Turned the switch on and tried to crank the engine did not see any spark coming from the points as they opened and closed.

thanks

Robert
 
You should have 12 volts at input to coil with switch on. The wire from coil to side of distributor should be 12 volts with points open, near zero volts with points closed.

If you have above zero volts with points closed, take a piece of paper grocery sack or cardboard such as from a cereal box and draw it through the closed points. Points contacts often develop an invisible film and this will often clean them to where they will contact.
 
(quoted from post at 18:50:08 04/01/18) You should have 12 volts at input to coil with switch on. The wire from coil to side of distributor should be 12 volts with points open, near zero volts with points closed.

If you have above zero volts with points closed, take a piece of paper grocery sack or cardboard such as from a cereal box and draw it through the closed points. Points contacts often develop an invisible film and this will often clean them to where they will contact.

Ok, thanks for the information. with the points closed there is a slight amount of volts showing like 0.171 so will try to run a flap from the point box through the closed points to see if that works.

Also will test the resistance of the coil.

thanks

robert
 
Went out today and passed the flap of the points cardboard container through the points when closed a cranked the engine and no spark. Then took some 400 grit sandpaper and passed it between the closed points with same result.

Placed voltmeter on ohms and testing the coil primary windings it read 1.71 ohms. Then placed the black test line into the coil after removing the coil wire and touched each external post. One side coming from the starter read 11 and the other side read 6.5 ohms. Is this normal or is the coil bad?

Thanks

Robert
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top