Question about coil!!

[scipper77]

I have a 1983'ish mercruiser 185. This is the 229 cubic inch and not the OMC engine. I am getting 5 volts across the coil. Also I have been pointed in the direction of one of 2 solenoids potentially being the problem.

I am trying to learn a thing or 2 about the coil here more than I expect to fix the boat as the motor is winterized and I'm not planning on touching the engine for months.

My questions...
I heard that automotive coils are cheap and easy to replace, Is this true for boats?? (No i did not look up any prices yet)

How do you check the condition of the coil using a standard meter? should i be looking for voltage drop, or perhaps internal resistance??

I think that if it's not difficult or expensive I might replace the coil this spring, but I would rather understand how to diagnose a bad coil than just go around replacing parts all willy nilly!

 

[Dunaruna]

Re: Question about coil!!

What is the actual problem, what symptoms are you experiencing?

Your ignition system has a resistor in line.

With ignition on, engine off, measure between coil + and engine ground (not coil -). With the points closed you should see 5 to 9 volts. With the points open you should see close to battery voltage.
Inspect coil for physical damage, cracks, oil leaks. You can do resistance tests on the coil itself but i don't have the values handy at the moment. When you do resistance tests, have a hair dryer handy so you can do the tests cold and hot.

 

[Bondo]

Re: Question about coil!!

Also I have been pointed in the direction of one of 2 solenoids potentially being the problem.

Ayuh,.....

So,.. What's the Runability Problem,..??

 

[scipper77]

Re: Question about coil!!

Thanks guys,
The original problem was that I would start the boat at home on the muffs and then 10mins later at the ramp it would not start. so next time out I started on the muffs and a few mins later tried to start on the muffs again and just a whole lot of cranking again. I posted here thinking it was a carb problem where the carb was dry after sitting but flooded after running and the guys here pointed me in the direction of the starter solenoid because I was only seeing 5 volts across my coil. As I had to winterize my boat this problem is still not resolved. Pulling the starter solenoid on my engine will require pulling the starter which seems like a lot of work when I am not even "sure" that this is the problem.

Having said that, what I specifically want to know here is how to test the coil. I am fully aware that to fix my specific problem there is a specific order in which tests should be performed to pinpoint the cause. That is not what I want to do here as the boat is buttoned up for the season. I want to learn about coils. If we are talking about a $20 dollar part here (??? I really need to look that up) I would have no problems just replacing the coil for piece of mind. what I do not want to do is replace the part as an alternative to testing it just to see if it makes a difference.

I apologize for confusing the issue by talking about the problem I was having and then asking about the coil only. There was no reason to bring up my past problem. I just want to test my coil if it's possible.

P.S. I believe I am seeing 5 volts with the points open (contacts open in the distributor). Does this make sense or would the boat not run at all if this was the situation?

 

[Don S]

Re: Question about coil!!

About the only thing you can test on a coil is resistance test to make sure it's within specs. There are other tests when loaded, buy you need a special (expensive) tool for that, and could buy a lot of coils for the price of a tester.

http://autorepair.about.com/cs/troubleshooting/l/aa062902b.htm

Just go to your OEM service manual for resistance specs.

 

[scipper77]

Re: Question about coil!!

Thanks Don, that's exactly what I needed to know.

P.S. I saved this question for the off season as a courtesy to guys like you don and bondo. I know it's annoying when guys like me expect you to answer a question that I could have probably figured out myself if I spent a little more time doing the research myself.
Again, Thank you, your knowledge has saved my time!!

 

[Don S]

Re: Question about coil!!

I know it's annoying when guys like me expect you to answer a question that I could have probably figured out myself

You do realize, we are not requiered to answer ANY question on this board, we do it because we want to. To go along with that, if we don't reply to a question, it doesn't mean we are annoyed, but possibly because it was answered by someone else or we may not know the answer.

 

[scipper77]

Re: Question about coil!!

You do realize, we are not requiered to answer ANY question on this board, we do it because we want to. To go along with that, if we don't reply to a question, it doesn't mean we are annoyed, but possibly because it was answered by someone else or we may not know the answer.

Don I know you guys don't have to help, you want to. that's why I make every effort to be as courteous as possible for any help I do receive. This site is without "any" comparison when it comes to getting thing fixed and it's because of guys like you Don.

Having said that, and in case I haven't said it enough, I sincerely do appreciate the help that I have received.

 

[180shabah]

Re: Question about coil!!

Scipper - if you do have a bad coil, then there is nothing "MARINE" about an ignition coil. you can get epoxy potted coils that hold up the vibration better, but the oil filled Merc (and inexpensive auto) coils seem to last plenty long.

Having said that, and in case I haven't said it enough, I sincerely do appreciate the help that I have received.

Ditto from southern VA.. Thanks to all

 

[9533Zero]

Re: Question about coil!!

I've gotten more help from this site, most of the time without ever having to ask a question, just reading old posts. Thanks to all!

 

[Cptkid570]

Re: Question about coil!!

I think there is only about a $10 difference between a coil from an auto parts store and one from ebasicpower.com