ingnition resistor wire/where is it

Westdevil

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some people said if you burn up points .it could be your ingnition resistor wire.<br /><br />470/170hp mercuriser<br /><br />burn points up after 9 times out
 

Dunaruna

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Re: ingnition resistor wire/where is it

Westdevil,<br /><br />Its quite common for points to fail because of a bad resistor - thats why there is a resistor. <br /><br />I don't know exactly where it is on your model but its commonly found in the ignition wiring loom near the starter motor. Its a piece of resistor wire spliced in, usually very flexible (more flexible than normal wire) and a different color. As a guide to finding it, follow the wire from the '+' terminal of the coil, you'll find it eventually.<br /><br />It supplies (about) 9 volts to your coil so as to not burn up the points. If you are getting more than 9volts to your coil (running) then you may also have a bad ignition switch. You will need to do some basic testing to nail the cause of your burnt points.<br /><br />Also take note of the advise given on your other thread.<br /><br />Good luck.<br />Aldo
 

Westdevil

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Re: ingnition resistor wire/where is it

i have 12 volts going to the coil+ side.<br />so is that my resistor wire bad<br /><br />or something else
 

achris

More fish than mountain goat
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Re: ingnition resistor wire/where is it

Westdevil,<br /><br />If the points are open when you measured it, it'll show 12 volts. The most common cause of burning points is the condensor. If someone has bypassed the resistance wire in the harness with a normal piece of wire then you'll also have burnt points. That one should be easy to spot. The reason you can't find this resistance wire is because it's in the loom and looks just like any other wire. Usually if that wire goes it breaks open circuit and you get not spark.....<br /><br /><br />Chris..........
 

Dunaruna

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Re: ingnition resistor wire/where is it

Chris, <br /><br />Unless the ignition system has had modifications, its has a factory fitted 9volt resistor. Any more will fry the points (and sometimes coil). I agree the condenser could be the culprit but 12 volts with ignition 'on' is too much. I'd like to here trents take on this. <br /><br />Aldo
 

elpaso

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Re: ingnition resistor wire/where is it

Any engine with points and condenser must have a resistor to lower voltage at coil from 12v to 8-9v. This low voltage,extends point life, greatly.<br /><br />Your ignition is wired - Purple 12v wire from main wiring harness,to choke on carburetor. Purple resistance 8v wire from choke to + side of coil. <br /><br />Quick fix - run a new wire from choke to + on coil. Install a marine bar resistor in this wire. They are cheap $6. Any marine parts store has them.<br /><br />Or - run new wire, and install new coil with Internal resistance written on side of coil. Such a coil will put out 8-9 volts.<br />Your present coil should have external resistor required, written on the side of coil. <br /><br />There is a second wire to + on coil. It comes from starter slave solenoid. It should be purple with yellow stripe.<br />When cranking engine, it will give you 12v to coil for a hot start. <br />When key is released, you run on 9 volts.<br /><br />I have wiring diagram, but I don't know how to post it to this site.
 

Westdevil

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Re: ingnition resistor wire/where is it

im getting 12 volts to the choke. its a white wire<br />looks to me it gose to the coil+ side from there.<br />at the coil there are two wires put together,as one.looks like factory made.one is the white one and the other one is tan.<br /> that sound right
 

elpaso

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Re: ingnition resistor wire/where is it

Old boat- some one has replaced wires -<br />Resistance wire has been removed.<br /><br />Give me 2 hours to find way to send<br />wiring diagram.
 

Dunaruna

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Re: ingnition resistor wire/where is it

Elpaso, if it helps, you can e-mail it to me and I'll post it.<br /><br />aldek@nex.net.au<br /><br />Aldo
 

Westdevil

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Re: ingnition resistor wire/where is it

can i buy resistor fuse to but in between the choke and the coil<br /><br />our just buy new coil that only puts 9 volts <br /><br />and how much is a new coil like that/
 

achris

More fish than mountain goat
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Re: ingnition resistor wire/where is it

I repeat! If the points are OPEN when you measure the voltage you'll get 12 volts! Draw the circuit out and look at it. It doesn't matter what resistance you have in a circuit, if the end is open then anywhere you measure on that circuit will show the supply voltage. Make sure the points are closed when you check the coil voltage!<br /><br />Chris..........
 

grizzlyadams

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Apr 23, 2004
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Re: ingnition resistor wire/where is it

ive got a 470 the best way to solve this problem is to install a electronic conversion. did this to mine and have never hqd to mess with it
 

Westdevil

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Re: ingnition resistor wire/where is it

ok went out side check to see if points where open.they are. and 12 volts<br /><br />closed points and i get 5 volts.12 volts at choke <br /><br />is that right.<br /><br />achris60 says you need to check to make sure they are closed is that right. and if so is 5 volts sound good
 

Westdevil

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Re: ingnition resistor wire/where is it

is there some one out there thats works on boats for a living .and could help me on this do the points need to be closed or open.to check the volts reading from the coil+ side<br /><br />help
 

achris

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Re: ingnition resistor wire/where is it

Westdevil,<br /><br />I am an electronics tech and I had my own boat shop in the 90's (qualified enough?).<br /><br />12 volts with the points open and 5 with them closed is right. 12 volts at the choke is also right.<br /><br />Have you changed the condensor?<br /><br />Chris...........
 

Dunaruna

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Re: ingnition resistor wire/where is it

Chris, <br /><br />Dish up the humble pie, I'll take my medicine. You're right.<br /><br />Westdevil, ignition 'on', points closed, test '+' terminal at coil - if battery voltage - ballast resistor is faulty or missing. If 8-9 volts - ballast is in line and o/k. You should be reading battery voltage when points are open.<br /><br />In my opinion, you need to establish if you have an operating resistor or not before you can proceed to other tests, your wiring description leads me to suspect it has been modified or otherwise played with.<br /><br />Aldo
 

Westdevil

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Re: ingnition resistor wire/where is it

ok achris60<br /><br /> i put new plugs/wires/dis cap/points/condenor<br />and rotor in last year. went out about 9 times.<br />could i have goting a bad condensor/points.<br />have you every had to change out a bad set<br />so did the resistor wire check out ok.<br />you said the volts sound right<br /><br />thanks for help
 

achris

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Re: ingnition resistor wire/where is it

Westdevil,<br /><br />Could you have got bad points/condensor? That is possible. Do you still have the old set? The other thing that'll burn points quickly is if the gap is set to close. Did you set them with a dwell meter or just a feeler gauge? Check that the condensor is properly grounded on the distributor plate, and that the distributor clamp bracket is clean. If your getting high voltage fed back from the coil through the points, that'll kill'em real quick.<br /><br />Chris..........
 
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