1973 Glastron Merc 140 Do I need to add a resistor to my coil?

[BahamaBarnBoat]

Just picked up a 1973 Glastron V-174 Bayflight. I got it started after replacing coil, and cleaning/sanding the points. Coil was .6 ohm ...probably what fried the points I replaced it with a 1.5 ohm coil. Based on the 2 wires to the + side of the coil I thought one would be a resistor wire. If it is a resistor wire should I still be reading 12 volts on the positive side of the coil when the engine is running?

1973 Merc 140 4cyl 181ci - YouTube

 

[BahamaBarnBoat]

Re: 1973 Glastron Merc 140 Do I need to add a resistor to my coil?

Here are some photos if this works

 

[thumpar]

Re: 1973 Glastron Merc 140 Do I need to add a resistor to my coil?

If it was a resistance wire it would show around 7-9 volts while the switch is on.

 

[BahamaBarnBoat]

Re: 1973 Glastron Merc 140 Do I need to add a resistor to my coil?

That seemed to work. Lets try the vid in case the link above didn't work

 

[BahamaBarnBoat]

Re: 1973 Glastron Merc 140 Do I need to add a resistor to my coil?

Thanks thumper...that's what I thought. I just can't find any info showing a resistor added to this engine? And why would there be two wires to the + side of the coil if one wasn't to start without resistance and one to run with. I know a bit about resistors and absolutely 0 about resistance wires.

 

[thumpar]

Re: 1973 Glastron Merc 140 Do I need to add a resistor to my coil?

Depending on the age it could just be a wire that actually has the resistance in it and not an actual resistor. My 1983 had the wire.

 

[BahamaBarnBoat]

Re: 1973 Glastron Merc 140 Do I need to add a resistor to my coil?

Could the wire have gone bad...lost it's resistance?

 

[thumpar]

Re: 1973 Glastron Merc 140 Do I need to add a resistor to my coil?

Not likely. Most of the time they will make more resistance to the point you can get 0 volts. It was probably replaced at some point by just a wire by someone that didn't understand the system.

 

[BahamaBarnBoat]

Re: 1973 Glastron Merc 140 Do I need to add a resistor to my coil?

You are probably right about not understanding the system. It has been bastardized. I think what I am dealing with is a motor that had been converted to a Pertronix II ignition at one time and back to points and condenser before I got ahold of it. The coil I took off of it to get it running was a Petronix Flame Thrower II with 0.6 ohm internal resistance. Now I am not sure whether I should go ahead and get a 3 ohm coil or an external resistor to use with the new 1.5 ohm coil that I have. You wouldn't know if checking the voltage on the - side of the coil is a valid test of the voltage going to the points do you?

 

[thumpar]

Re: 1973 Glastron Merc 140 Do I need to add a resistor to my coil?

The Pertronix unit would explain the full 12v. I converted my old boat to a Pertronix and enjoyed not having to worry about points. I would either convert it back to original or go full Pertronix, no half of one and the other.