new coil - still no spark

[rooooney]

I just purchased a new coil because I am not getting a spark- I hooked up the plug wire from the new coil to a spark tester and still no spark- Is it safe to assume that my problem is between my battery and coil?- my distributor and or rotor are involved post coil correct?

Where what and how should I test with my new multimeter to resolve this problem?

 

[maxxman04]

Re: new coil - still no spark

with multimeter, check the + side of coil, should have minimum 12volts, with key on. if not, then problem lies between coil and ignition switch. also, check for 12 volts at the ignition switch itself (should be red or yellow wire, larger than rest) with key off. turn key one click, to the RUN, not the start, position. 12 volts should appear. if yes, trace thru kill switch, back to coil, key still in RUN position. should have 12 volts all the way back. if no voltage at ignition switch, problem lies between battery and switch. it takes a bit of tracking and tracing wires down. a manual with a wiring diagram for your boat will help greatly.

 

[rooooney]

Re: new coil - still no spark

So i should have 12 volts through pretty much everything (from switch to coil) and that's with the key on- not actually cranking? (The motor cranks hard, Just no spark).

 

[Bondo]

Re: new coil - still no spark

Ayuh,... It'd be nice to know just What the 'ell you're workin' on....

Is it Point fired Igntion,..?? Have you checked the Points,..??

 

[Don S]

Re: new coil - still no spark

Coils are not the first thing to consider when you have a no spark condition. I would love to have a nickle for everyone that was changed for no reason.

First thing one needs to know is what you are working on, and what kind of ignition system you have.

 

[maxxman04]

Re: new coil - still no spark

agreed, specifics as far as type of ignition, motor, boat, would help. to answer, yes, the whole boat runs on 12 volts. with the ignition off, you will not get any voltage to alot of boat, especially the motor and ignition, but in the run position, everything will have power. least it should (unless it's on switched power, in which case you will have power to the switch)

 

[rooooney]

Re: new coil - still no spark

its a 1969 - inline 4 - 120hp omc- all old stuff so everything I replace is for the best- I really do not know too much about this- but the coil feeds the distributor - correct? So if I can not get a spark out of the coil then my problem should lie before the distributor and points. Correct? I'm not trying to sound like a smart Alec - I really don't know.

 

[PNW Driver]

Re: new coil - still no spark

That's the exact year, motor, and symptoms of my boat. I did the same thing. New coil, no help. Points "looked" good. Took them out, cleaned them, regapped them and presto* it runs great. My cash is on the points.

 

[Don S]

Re: new coil - still no spark

"CLEANING" points is nothing more than a test. If you get spark, then they were probably glazed over or corroded and caused the problem. Cleaning also damages the surface of the points.
They are cheap, replace them yearly by doing a tuneup in the spring to make sure your motor runs all season long and keeps you off these forums with problems like this.

 

[PNW Driver]

Re: new coil - still no spark

Point taken. Mine were not corroded they just had a film of oil over them. The new ones are in the tool box as we speak, along with the condensor.

 

[rooooney]

Re: new coil - still no spark

My points are brand new- am i right to assume though that my distributor is not the problem if I can't get my coil to spark?

 

[Don S]

Re: new coil - still no spark

am i right to assume though that my distributor is not the problem if I can't get my coil to spark?

I would assume nothing. Do you have the dwell set right, even the point gap? wires hooked up right, have you ever worked on a points distributor before? Have you ever done engine repairs before? Do you have a manual of any kind?
Please answers ALL the questions, not just one.

 

[J. Mark]

Re: new coil - still no spark

on a points type ignition, you have a resistor wire running to the coil. Your volatage is stepped down except when cranking (sorry I don't remember the exact voltage but I think it is around 7-8 volts. When cranking only you get 12 volts through the second hot wire that is on the additional post on the starter (The one that energizes the solenoid)

Condensers get a bad rap, but are rarely bad these days. get a fresh set of points on the distributor. Set them properly and use a multimeter to check voltage to the coil.

 

[rooooney]

Re: new coil - still no spark

I have done many engine repairs before but I have not worked on a points distributor before. I will work on the dwell and check the gap again. My manual says to pull the center plug from the distributor (still hooked up to coil) and hold it near a ground. Then crank engine and look for spark. I did this and there is no spark (I used a spark tester). During this test I concluded that at this point nothing is hooked to the distributor - so the -no spark problem- must not be in my distribtor- not to say that there may not be a problem with my points too but if my coil isn't sparking then the distributor dosent reAlly matter at this point. But I do plan on checking the gap and dwell on my new points.

 

[Bt Doctur]

Re: new coil - still no spark

"I have done many engine repairs before but I have not worked on a points distributor before"

Do you actually know how points work to produce spark?
Do you know how to properly install and "gap" them on the high side?
Do you know how to check the opening and closing with a meter?
http://www.boatfix.com/merc/Servmanl/13/13B4R2.PDF

 

[JustJason]

Re: new coil - still no spark

i've gotten bad condensors out of the box. with the condensor out on some kind of nonconductive work surface put your meter on resistance and hook it up to the condensor. make sure your not touching it when you do this. the meter should slowly reach infinity as it's charging the cap... if it doesn't you have a bad condensor.

 

[Maclin]

Re: new coil - still no spark

During this test I concluded that at this point nothing is hooked to the distributor - so the -no spark problem- must not be in my distribtor- not to say that there may not be a problem with my points too but if my coil isn't sparking then the distributor dosent reAlly matter at this point. But I do plan on checking the gap and dwell on my new points.

Dude, that is so wrong of an assumption....the points are what the distributor opens and closes to produce the spark from the coil, then it distributes the generated spark to the appropriate spark plug wire.


As far as what tells the coil to fire, basically the negative wire is grounded then ungrounded for each cylinder. On a points setup that is what the points do, ground then unground the coil negative wire.

A coil is really a transformer with a primary coil and a secondary coil. The secondary coil has many more windings than the primary. Any voltage put thru the primary is multiplied by whatever ratio of the secondary to primary windings. The flip side is the current available from the secondary coil is reduced in lockstep with the voltage increase, but higher voltage is what we need to jump the spark plug gap.

The primary coil is what the positive and negative terminals connect to. The secondary coil is what the coil tower is connected to. They both ground thru the negative terminal. When the coil is grounded that creates magnetic flux lines from the primary coil to cut across the secondary side. When the primary side is ungrounded the magnetic flux lines collapse and induce a voltage in the secondary windings and that energy goes out the large coil wire into the distributor cap then on to the sparkplug wire thru the rotor.

The length of time that the coil is grounded is called dwell, the longer the dwell the more flux lines can build and thus the more energy produced in the secondary side when the lines collapse. While the grounding of the coil produces a voltage in the same manner as the ungrounding, the ungrounding "cycle" is what is used to produce the spark. All of this is controlled by the phasing of the points opening and closing event mechanics inside the distributor.

SO bottom line, the distributor has a lot to do with your no spark condition.

 

[bruceb58]

Re: new coil - still no spark

You need to answer Don's questions.

Have you set the dwell or point gap?

 

[rooooney]

Re: new coil - still no spark

I did set the point gap - I do not have a dwell meter so I have not done that- I am reading 12v from the positive terminal of the coil now. Still no spark though

 

[JustJason]

Re: new coil - still no spark

hook up a test lead on the - side of the coil and rapidly strike it against ground. Don't hold it on ground. Just tap tap tap. If you get spark then your problem is in your points.