1972 merc 165 6cyl wiring diagram

"need help with a voltage prob

"need help with a voltage problem,does anyone know or have a diagram or can tell me what the voltage drop should be on the ballist resistors,there are 2 side by side and on the wire going in on the first one I have 12.2? hten it drops to 8.4 then on the next one it goes from 8.4 to 7.1,I need at least 9 at the coil and I'm only getting 5.7,they are new ballists but they may not be the right ones,also if I leave the key on,the first one will start to smoke,some body else made this mess and I was asked to clean it up.HELP!!!!!"

"I would disconnect the second

"I would disconnect the second one and run with that, or you can throw that all away and get a Pertronix Ignition kit, 30 min or less install -Start-Fin.. and no more points, or ballist.. etc.. WAY Betterer !!! "

"I'm w/Brian. Whomever cr

"I'm w/Brian. Whomever created the mess didn't want to get a new resistor wire. "

"problem is it is a vintage cl

"problem is it is a vintage classic and he wants it original,none of my diagrams match the set up I'm looking at,they don't go back that far,I was looking at the diagram today and I was looking for the resistor wire but without the RIGHT diagram it made no sense,soooo,with all the hacking and cutting thats been done I really want to just rewire the thing but it has to be right ,I mean ,"somebody" hacked a wire from the starter to the coil,I could see how that would give him a power supply,but apparently it stopped working cuz it gots no spark,so again ,does anybody have the RIGHT diagram so I can just rewire and do it right?"

Look at a 120 or 140 for that

Look at a 120 or 140 for that year; the wiring should be the same. There should be a wire from the starter to the + side of the coil. There is also another purple (resistor) wire to the same terminal. The ignition gets 12 vdc when cranking from the starter and w/the ign. key in the run position the resistor wire drops 12 vdc to 9 vdc. Look around for the resistor wire.

I believe the actual wire you

I believe the actual wire you are looking for comes from the harness and is typically run down thru the harness towards the altinator and then back due to its length. It is a purple/white wire I believe and the actual wire inside is NOT copper. I believe it is some other material and looks aluminium in color. It is very stiff and kinks easily. If you can identify where it connects into the harness measure from that point to its end where it would connect to the coil. It has to measure I believe 1.8 to 2 ohms.

Do the same for the other "wire" and if it does not equal those numbers cut it out!!

If all else fails find the 12 volt ing wire in the harness go to a aouto supply and purchase a new ballist resistor or resistor wire and start from scratch.

"Thank you gentlemen,I will ke

"Thank you gentlemen,I will keep you apprised."

I think the Clymer manual that

I think the Clymer manual that I have for my 1973 Inline six has the diagram for the older ballast type wiring diagram. I will have a look in my manual and let you know. If it does I will send you a copy in the mail if you want.

Eric

"KGHOST has detail pretty clos

"KGHOST has detail pretty close. I actually owned one of these, with a vertical HX (FWC). The resistance wire is a grade of ni-chrome and has a white jecket with a purple trace. It is 'spliced into' the engine harness and is usually hidden under the tape. when we changed it we made a couple 'loops' (folds) vs just one so we didn't re-wrap most of the harness."

"okay,heres the latest,owner d

"okay,heres the latest,owner does not believe that there needs to be a wire from the starter to the coil,he says that would send 12 volts to the coil and he only wants to put 9 to it.NOW...can I run 12volts to the one ballast resistor and basically hot wire the system ?See,I know what I need to start this thing ,problem is even when I put 12 to the resistor ,I only get 7 out the other end,I have been told by my parts guy that there are different resistors,this I know,problem is that the owner bought the set that we are using and I don't think they are the right ones,thier not even marine,they were bought at pep boys.Now for my question,being that he wants to by pass the harness,can I use ballasts that my merc dealer recommended from volvo or crusader,and run 12 to the resistor and jump the starter,the only problem there is that usaully when I jump a system I go with 12 to the coil and just hook a jump box to the starter and off we go.Right now I can't get any spark even when I go with 12 to the coil,but the coil calls for a resistor so it should work going 12 to the resistor,problem is I still go from 12 to 7 on the ballast,I just gotta make this thing run and its makin' me nuts!! come on guys ,its time to pull the rabbit out of the hat.So heres what I want to do,get the right resistor and hopefully get 12 and 9,then hook 12 to the resistor and put the wire back going from the coil to the starter and I should get juice on both sides of the coil when I crank and spark at the points ,RIGHT? NO he won't even concider a better system because he thinks it will only make more problems and he does not want to tear into the harness until he is convinced that it can be started after the ballsts,I know the resistor wire is the problem and I can deal with that once I get it running with the bybass set up.HEEELLLP!!!!!"

WHY AM I DROPPING FROM 21.3 TO

WHY AM I DROPPING FROM 21.3 TO 7 THROUGH ONE FRIGGIN' RESISTOR !!!!!!!!

"Lets hope your saying from 12

"Lets hope your saying from 12 to 7 volts...

The drop across the resistor is due to its resistance (ohms). you can cut the drop in half by paralleling TWO resistors, assuming they are the same value. This will cut the voltage drop to ~2.5 V so is 9.5 close enough?

If that's close enough, then convince him the wire from the solenoid, direct to the coil, is okay because it only is there for a short time - only when the starter is cranking. It won't be 12 volts either as the starter's current draw will induce a drop in the interconnecting wires. You can 'test' it by hooking it up and pulling the coil wire out of the cap (ground it, thru a plug if you want a 'tester'.

BTW, the resistors come in different values to 'match' the different coils. The coils are desired to handle only so much current, the resistor limits the current to that value, if properly selected. Your hunch about the wrong resistor seems very reasonable."

"The wire from the starter to

"The wire from the starter to the coil is necessary as during cranking there isnt' really enough volts and amps through the resisitors, especialy if the batt gets low.

I've seen the resistors in parallel. you want around 9V with the key in the ON and 12Vish When cranking.

If you cant get running you need to check or replace the condensor, even a new one can be bad !!, triple check the point gap, check that the points to the dist isn't grounding. Sometimes a bad tach will cause the ignition to fail.

Make sure the shift interupt switch isn't activated too"

"Now all I have to do is convi

"Now all I have to do is convince HIM that the wire needs to be there and that the NEW condenser that he put in could be the problem.Now,if I go with 12 to the resistor I should get 9 out the other end ,why am I coming up with 8.4 ? ,I've bypassed the ignition and I still come up short,is it to do with the starter wire,now....how can I by pass the shifter?see,ya' gotta understand that nothing is how it should be because "some body" hacked it before I got there.Otherwise she would be running already.So I'm gonna do it the way I should have to start with,use the other coil he has that was tested and is good,new points and condenserand put the friggin' wire back on the starter.What about hte voltage drop though?that makes no sense to me and his explanantions of proir work just confuses things even more.Hey,I really appreciate you guys helping me out,I'm sure you have had at least ONE job like this,I just wanna' walk away with a smile and say ,"well now ,was'nt that fun"!."

"Maybe Printing out this post

"Maybe Printing out this post will help you.

so a good charged battery is 12.7 right ? Now check the voltage before the resistors and see what you have. 8.4 isn't far from 9.

Bypass the shifter? need a little more info here, are you talking about the Neutral Safety ?

The shop I work at has an old Coil and Condensor and Points Checker (scary thing- makem HEAPem Sparks !!!) So it checks condensors, and I've seen a few NEW ones that didn't pass. And I fought with a set of points for a couple hours, changed out 2 Full SETS!!! P&C then just put on a Pertronix Kit and NEVER looked back. Started even when the engine was flooded from pumping the throttle.

ps, even if I was in some "classic" boat show and lost 1 or 5 points for NOT having Points.. I STILL wouldn't run points !!"

"I only wish he was not so set

"I only wish he was not so set in his ways and would be honest with what has really occured,I may have to walk away from this one because he does not want to pay me for the time to get to the problem and with his lack of knowledge and not telling me what really happened and the fact that he is getting BAD info from some where,its just not worth the trouble,but I really hate to walk away and feel like I have failed,,as we said in the marine corp,"failure is not an option"!"

Some of the voltage drop is fr

Some of the voltage drop is from the 1972 wiring that has internal corrosion. I would set my foot down w/the #$%&@* customer and say either he pays for a new engine wire harness or you walk.

"I was hoping not to have to w

"I was hoping not to have to walk away from an unfinished job.I guess I am going to have to sit him down and try to explain it to him ,I'll print out this thread to verify my efforts and leave it up to him.Thanks guys"