SOLVED!!! Purple resistance wire ????

[skynyrdcat]

86 Mercruiser (B407574) 3.0 181cid I/L4

Just bought it recently (it's been parked for a number of years) but it's in pretty good condition (It's in a Searay cuddy stren drive by the way).

Doing some work to get it ready and when I was checking some electrical components, I found that the "purple resistance wire" (as it's called in the wiring diagram) going into the coil was hot (starting to smoke). This same wire also ties into the choke and alternator, then into the main harness.

I see where it goes, but I'm not sure what it's for????

Any thoughts on why it would get hot. No work has been done on the boat to my knowledge (other than a new key switch was out in because when I took it out to look, I saw that the original connectors had been cut off and the wires were "wrapped" around the threaded terminals).

Thanks in advance!

 

[Maclin]

Re: Purple resistance wire ????

Re: Purple resistance wire ????

If you have the key on and engine not running then that wire will get hot depending on if the points are closed or open. Leaving the key on for a long time can harm ignition components like the points and coil, and the resistor will definitely get hot if the points are closed.

Also, the terminal must have a good electrical connection to the wire, just wrapped around is not good enough and, as you seem to suspect, will add resistance and associated heat. Crimping is the only acceptable method for a terminal connection to the end of a wire.

 

[Maclin]

Re: Purple resistance wire ????

Re: Purple resistance wire ????

The resistor wire is part of the coil power supply circuit and is commonly called ballast resistance. This is necessary for most coils to even out the load as they heat up in use during varying rpm conditions. Typically this reduces the coil positive voltage to 9-10 volts. During cranking this wire is bypassed and the coil gets a full 12 volts then.

I hope you do not have wiring problems, I would want to get a manual with the proper wiring diragrams and trace it out. Some boat owners do not understand the difference between this type of system and the ones in a car that usually have a solid ballast resistor component somewhere instead of the long resisitance wire found in this type of engine setup in a boat, and do not respect it's position or value and cob it all up sometimes when debugging a wiring issue.

 

[jerryjerry05]

Re: Purple resistance wire ????

Re: Purple resistance wire ????

The coil works best at 9-10 volts 12v in will overheat and burn out the system. If you are in doubt get a coil with an internal resistor,any auto parts.Jerry

 

[skynyrdcat]

Re: Purple resistance wire ????

Re: Purple resistance wire ????

The resistor wire is part of the coil power supply circuit and is commonly called ballast resistance. This is necessary for most coils to even out the load as they heat up in use during varying rpm conditions. Typically this reduces the coil positive voltage to 9-10 volts. During cranking this wire is bypassed and the coil gets a full 12 volts then.

I hope you do not have wiring problems, I would want to get a manual with the proper wiring diragrams and trace it out. Some boat owners do not understand the difference between this type of system and the ones in a car that usually have a solid ballast resistor component somewhere instead of the long resisitance wire found in this type of engine setup in a boat, and do not respect it's position or value and cob it all up sometimes when debugging a wiring issue.

WOW! I too didn't realize the difference between this set up and standard automotive, and yes the key was left on for about 15 minutes (while I was checking voltage at various locations).

I agree with the terminals on the wiring and I'll pick up some terminals this evening before I get home.

Thanks again for the information.

 

[Maclin]

Re: Purple resistance wire ????

Re: Purple resistance wire ????

Good luck!

 

[bomar76]

Re: Purple resistance wire ????

Re: Purple resistance wire ????

WOW! I too didn't realize the difference between this set up and standard automotive

That's the way automobiles were wired for many decades......untill electronic ignition came along.
Either a resistor wire, or a coil with internal resistor.

 

[paulrfrancisco]

Re: Purple resistance wire ????

Re: Purple resistance wire ????

Or an inline Ballast resistor module located on the firewall or inner fender

 

[bomar76]

Re: Purple resistance wire ????

Re: Purple resistance wire ????

Yep, those also....

 

[skynyrdcat]

Re: Still need help Purple resistance wire ????

Re: Still need help Purple resistance wire ????

Still need help

Put terminals on all the wire, but the purple wire still gets hot (it gets very hot in less than a minute).
Purple wire has continuity to the engine block.
Un hooked battery ground and it still has continuity to block)
Un hooked main harness (to isolate front of boat from the engine compartment) and it still has continuity.
I literally un hooked each wire (starter, alternator etc) one at a time and checked after each wire and still continuity to block.

I can find no breaks or damaged insulation.
Was hoping someone on here with more wiring experience could tell me any other features (tilt/trim motor, blower, etc) that might tie these circumstances together.
One other thing, the purple wire has direct continuity to one ground wire specifically (hooked to the battery or not) the other two ground wire do not have continuity to the purple. It's a medium gage ground wire (not the big one) that goes toward the control panel (haven't got everything apart yet to see what it hooks to).
blower fuse blows immediately when turning them on, none of the others do.

Sorry so long, but maybe you're experience can point out something that it may take me several hours to find.

Thanks a million!

 

[Don S]

Re: Still need help Purple resistance wire ????

Re: Still need help Purple resistance wire ????

Disconned the purple wire from the choke coil and check it.

One other thing, the purple wire has direct continuity to one ground wire specifically

I would be tracing that black wire to find out WHERE exactly it's connected or touching the purple wire.

 

[Maclin]

Re: Still need help Purple resistance wire ????

Re: Still need help Purple resistance wire ????

Also make sure the purple resistance wire is the correct length and has not been shortened up.

 

[skynyrdcat]

Re: Still need help Purple resistance wire ????

Re: Still need help Purple resistance wire ????

Disconned the purple wire from the choke coil and check it.

I DId



I would be tracing that black wire to find out WHERE exactly it's connected or touching the purple wire.

I am!
I'm a bit nervous, the boats been parked for a while and I don't know if I've got all the wasps out of it yet lol and I don't like those lil dudes and they don't seem to like me either!
I'll start pulling the panels today to see where it goes.

 

[Limited-Time]

Re: Still need help Purple resistance wire ????

Re: Still need help Purple resistance wire ????

You may want to start your trouble shooting with a large tarp, and a bug bomb or two......................to keep the pain to a minimum so to speak.

 

[skynyrdcat]

Re: Still need help Purple resistance wire ????

Re: Still need help Purple resistance wire ????

Both small starter solenoid posts have continuity to the block (with the wires unhooked) and the wires have no continuity when they ALL are unhooked.

Starter must have some heavy rust or moisture inside.

Thanks for all the input guys, I'll get this thing apart soon and see the extent of the damage!

By the way, I think I got all the wasps this morning (with no stings).
At one point I was laying in the carpet neXt to a shed snake skin amists 16 dead wasps. If someone had slaped the side of the boat and yelled, I would have probably had to change underwear! LOL

 

[CharlieB]

Re: SOLVED!!! Purple resistance wire ????

Starter ohms are correct, not related to your problem.

Closed points and electric choke are each serious current draw key ON and engine OFF, purple also is the alternator trigger to turn on the regulator, not normally much current draw unless there is an internal problem.

Disconnect all three and retest, reconnect and test only one at a time.

Consider upgrading your points ignition to the pertronix breakerless kit, listed in the Sierra catalog and available through this site.

Blower is a separate circuit, motor may be toast.

 

[HT32BSX115]

Re: Still need help Purple resistance wire ????

Re: Still need help Purple resistance wire ????

Uh......you know, (maybe you already did this) A lot of people are allergic or eventually become allergic to bee/wasp stings.

You REALLY should get a shop-vac and carefully go over that boat with it before you get yourself into a situation where you might need call 911!!



Cheers,


Rick

Both small starter solenoid posts have continuity to the block (with the wires unhooked) and the wires have no continuity when they ALL are unhooked.

Starter must have some heavy rust or moisture inside.

Thanks for all the input guys, I'll get this thing apart soon and see the extent of the damage!

By the way, I think I got all the wasps this morning (with no stings).
At one point I was laying in the carpet neXt to a shed snake skin amists 16 dead wasps. If someone had slaped the side of the boat and yelled, I would have probably had to change underwear! LOL

 

[skynyrdcat]

Re: SOLVED!!! Purple resistance wire ????

Starter ohms are correct, not related to your problem.

Closed points and electric choke are each serious current draw key ON and engine OFF, purple also is the alternator trigger to turn on the regulator, not normally much current draw unless there is an internal problem.

Disconnect all three and retest, reconnect and test only one at a time.

Consider upgrading your points ignition to the pertronix breakerless kit, listed in the Sierra catalog and available through this site.

Blower is a separate circuit, motor may be toast.

I ordered the points set (arrived today).
I ordered a starter too, when I got inside mine it was incredibly rusty and I had to replace a couple of contacts inside the solenoid. Just didn't want t take a chance in it getting hot or giving me problems when I'm on the lake surrounded with bikinis instead of wasps! lol

I haven't verified the actual points, but I have voltage on both sides of the coil with the key on, plus something that's sat that long could use the full tune up anyway.

I'm not allergic by the way, I haven't had a sting in years (the last one got my attention enough to make me very leary). The only thing I had available was starting fluid (which I do not use for anything anymore) so it was handy for wasp spray.


Thanks for the help guys, if I have any more problems I know where to come to!