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Merc 115 spark wires

S

sullybe

Contributing Member
I just tried to start my 115hp

I just tried to start my 115hp merc after a very heavy 3 days of rain. It sounds like I have no spark.So I was going to change the wires. I can think of no other reason for it to not start from dampness.When I pull a wire from the distributer there is a wax like substance in the hole for the plug wire. Does anyone know what this is and should I get more to replace the wires.

Thanks Dan
 
"Daniel, That stuff is likely

"Daniel, That stuff is likely some dielectric grease. I would wipe it off. Check for spark at the coil. The coil side of the coil to dissy wire pulls out. Unscrew the coil wire from the dissy cap and put it back into the coil and crank the motor. If no spark, check to see that the white wire, under the red wire on the switchbox (non-dissy side)has +12V, as does the red wire."
 
"I checked for spark and had n

"I checked for spark and had none at plug so I worked back. I didn't have to far to go when I opened the distributer I found the small contacter in the middle of the cap had broken apart.The contacter looked like a piece of graphite on the end of a spring. I have tried to buy one at the local marina but they want to sell a whole cap. This piece looks like it is seperate, the spring comes right out with little efort. Does anyone know where this little piece would be available??
Thanks Dan"
 
Your local starter alternator

Your local starter alternator shop will have suitable material-----you may have to file / whittle it into the correct shape---I am sure you have the time and can do this.
 
"Dan, That center electrode sh

"Dan, That center electrode should still be available at a merc dealer. I bought a new one last year.

If they do not have it, try to order it from the Dougrussell.com or Crowleymarine.com web sites.

BTW - The cap is $100+"
 
"Thanks Chris,the price I got

"Thanks Chris,the price I got from my local dealer was 145.00 and they didn't even know if they could get it. I will try those sources.
Thanks Dan"
 
I bought the center spring and

I bought the center spring and brush for the distributer and installed it.Still no spark. I have spark going to the coil. I think i'm losing it in the distributer.I pulled the wire from the coil to the distributer and had spark there.The rotor and cap look good. What else would stop the spark in the distributer??

Dan
 
The rotor and cap " look g

The rotor and cap " look good " means nothing.You need to take those parts to a good shop that can test the parts.My bet is the rotor.Now before you go prying on that rotor find out if it can in fact be removed from the shaft ( some cannot ).A good shop and a good mechanic are " priceless "
 
The rotor can not be taken off

The rotor can not be taken off. Is there some way to check it without taking the distributer off the motor.
Dan
 
I guess you can use an OHMMETE

I guess you can use an OHMMETER to check from where the carbon touches to ground.--------If you get a spark that will jump a gap of 7/16" from the coil and you have a known good cap it would make the rotor very suspect.
 
"Dan, it would be surprizing i

"Dan, it would be surprizing if the rotor has failed. Your next step is to measure the resistance in ohms, from the dissy cap thru the plug wire to the spark plug boot. The wires are stranded stainless steel, and the resistance should be zero. The boots are replaceable for small money. The wires can be gotten at oldmercs.com for ~$6 each."
 
"Thanks Chris, I am going to b

"Thanks Chris, I am going to bring home a good multi meter from work this weekend. I planed to check the stator, trigger, coil,cap and rotor. I have spark going to the cap but I don't know how good it is. Also I pulled the lead out of the center of the cap and either it had no end on it or the end is stuck in the cap. I tried to get what looked like a lead piece out but it wasn't coming out easily. Is there not a cotactor on the end of the wire or do I have it stuck in the cap. I didn't want to force it out and ruin the cap."
 
Great info. I have aquired a 1

Great info. I have aquired a 1971 80hp and I am trying to install the cap and plug wires. Does anyone know the firing order? I don't know which wire goes where.
 
"Daniel, is there a brass or c

"Daniel, is there a brass or copper end on the coil lead,center of cap, if not, its stuck in the cap,work it out gently,the other leads are threaded and screw out,out of idle curiosity, have you looked and checked the plug leads?
Bob, the cap fits on only one way,it's also numbered,as is the block,1-3-2-4 is the firing order,if it's 4cyl.If it's 6cyl,I have no idea.
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"Noel,the copper end of the co

"Noel,the copper end of the coil lead must be stuck in the cap. I have nothing on the end of the lead and what looks like the end is stuck in the cap,I tried to get it out but it was not coming and I didn't want to force it. Any chance that srews in to? I have not checked the lead ends, I had planed to this weekend but work and weather prevented it.Thanks for the info on the cap leads, I didn't know they screwed in.
Bob the firing order for a 6cyl is stamped on the back of the engin."
 
"No,in my limited expiernce,I

"No,in my limited expiernce,I own a'69 model,the coil lead pushes in. A small screwdriver,GENTLY pry the lead crimper in,be very careful,these caps are hard come by and expensive,grab with a long nose pliers and work,might help to soak in wd40 for a day or two,good luck."
 
"Noel, got a chance to work on

"Noel, got a chance to work on motor a little today.The wire from the coil to the distributer does screw out of the distributer, this made life easy. I made up a new lead but still no firing. I noticed the spark plugs, that are very new have a black like soot around the white part of the plug just below the boot,any idea what would cause that? Also the inside of the boot looks rusted."
 
"Hi Daniel,Maybe someone might

"Hi Daniel,Maybe someone might have changed what should be on mine,though when I changed the leads the replacement didn't have a threaded end.
Back to your problem,are the plug leads the original '70s'? I'm told these have a graphite core and this might be breaking down causing the black soot on the plug or a break in the core causing the spark having to jump.Have you done a continuity test on the leads? Might be worth changing the leads."
 
"Hi Noel,I haven't checked

"Hi Noel,I haven't checked the spark plug leads but I checked the trigger and the coil. I found a bad end on one of the trigger wires, I replaced that. The coil has continuity between the possitive side and the ground. The book says I should have resistence not continuity so I am thinking I have a bad coil. I will check the plug wires,but they look old so I will most likely replace them."
 
"Hi Daniel,.01-.03 is very sma

"Hi Daniel,.01-.03 is very small,and the coil can give a continuity reading between + & -.According to the seloc book. I would do the plug leads first and test for spark,$170+ for a coil would entice me to spend an extra day or two checking it out
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"Hi Noel,I will check it out f

"Hi Noel,I will check it out further,I don't want to buy a coil if I don't have to. I read the Seloc book and every test they have for a coil shows no continuity or resistence. I only had a small multi meter,I will take the coil to work where I have some better equipment. With the key on I thought I would have power to the positive side of the coil but reading the book it seems that it dosen't get power to the positive side until the trigger sends a signal. Is this right,every engin i've had before always had power to the positive side of the coil when you turn the key on.(not outboards)"
 
"Hi Daniel,the resistance is s

"Hi Daniel,the resistance is so small that it would be difficult to see,that is between the (+)and(-)on the R x 1 scale.
That is my reading of it as well,reading you post Oct. 14,you say you have spark at the cap,and the brush has been replaced,is it fully home?I would think either the cap is damaged inside,eg. cracked or the,me not knowing the correct name,internal contacts were damaged when original brush broke up, or corroded.If that is the case,I'm thinking you will need a new cap. If the coil is us. I doubt if it would send spark to the cap
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I would put it all back ,borrow a lead from the auto or from friend and crank.It'll be either
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or
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"Hi Noel,I put a spark tester

"Hi Noel,I put a spark tester on the coil and I disconected the lead and had the same results with both.When you turn the key on you have a spark. When you crank the engin there is no spark.I also tested all the leads from the inside of the cap to the spark plug and they are all good"
 
"Hi Daniel, <[img]"http://www.

"Hi Daniel,
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You should have no spark until you crank the motor,sorry to be the bearer of bad news but it sounds like you coil has got to go where all bad coils go,the recycle bin."
 
"Hi Noel, Put in a new coil an

"Hi Noel, Put in a new coil and same results,so I am moving back to the switch box to check that out. Do you know of an easy way to do that or should I just take it out and bring it to a shop.

Dan"
 
"Hi Daniel,I don't know of

"Hi Daniel,I don't know of an easy to test,I would suggest the shop,they will have the proper testing equip.But I sincerely hope it's not the switch box as these are very hard on the wallet.
If any of the other good people know of a handy way please let us know as it's 100 miles to the guy I know.
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"The switchbox is one of those

"The switchbox is one of those things that you prove is the problem by testing everything else and seeing that they work.

There is no test to tell if it's working or not working - if the rest of the ignition system checks out, you replace the switchbox..."
 
"Daniel,There is a saying,RTFT

"Daniel,There is a saying,RTFT,so I did,switch box can be tested by,and here's what I didn't see before,an ignition analyzer.I have no idea what that is.Graham is right, if everything else checks out ok,it's the switch box and Graham has forgotten more than I'll ever learn if I should live to be a hundred. I was browsing ebay,there are a couple of switch boxes,only problem is if they are good how long they would last"
 
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