resistance wire

civicsi1279

Seaman Apprentice
Joined
Aug 27, 2008
Messages
30
i have an 85 3.7 mercruiser. what color is the resistance wire and were would it be. i'm not getting any spark @ the coil and nothing @ spark plugs. is there a difference between a ford coil and the mercruiser coil or are they the same.
 

Fishermark

Vice Admiral
Joined
Oct 19, 2003
Messages
5,617
Re: resistance wire

On the positive side of the coil there will be two wires - one coming from the starter, the other wire is the resisitance wire.
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: resistance wire

i'm not getting any spark @ the coil

You don't get spark AT the coil, you get spark from the coil. When checking spark with the engine not running and while cranking the engine with the starter, the resistance wire is bypassed anyway. So even if it was broken off, it would start, then, as soon as you let off the igntion key it would stop running.
Do you have power to the + terminal on the coil when cranking? IF so, then that probably isn't your problem. You most likely have old points that are glazed over and will not make good contact. You can hit them with a point file and see if it has spark, if it does, get some new points.
ANY points distributor in a boat should have NEW points and condenser YEARLY. How old are yours?
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: resistance wire

You don't get spark AT the coil, you get spark from the coil. When checking spark with the engine not running and while cranking the engine with the starter, the resistance wire is bypassed anyway. So even if it was broken off, it would start, then, as soon as you let off the igntion key it would stop running.
Do you have power to the + terminal on the coil when cranking? IF so, then that probably isn't your problem. You most likely have old points that are glazed over and will not make good contact. You can hit them with a point file and see if it has spark, if it does, get some new points.
ANY points distributor in a boat should have NEW points and condenser YEARLY. How old are yours?

You see... Here's where I make my mistake... I assume that people have done the basic checks... Don really is the Sensai... He assumes everybody comes running straight here without checking ANYTHING... and he's right most of the time. ;);)
 

civicsi1279

Seaman Apprentice
Joined
Aug 27, 2008
Messages
30
Re: resistance wire

the points were replaced about 2 months ago.and i am getting power to the coil.i gapped the point at .016. is that correct. i havent had any problems until couple days ago
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: resistance wire

the points were replaced about 2 months ago.and i am getting power to the coil.i gapped the point at .016. is that correct. i havent had any problems until couple days ago

Did you do the test I recommended? If so, what was the result?

Chris........
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,344
Re: resistance wire

Assume nothing. do you have voltage at the + side of the coil with the key in the run position? Yes or No
Yes= wiring is good,
Other no spark causes are:
glazed over points
bad wire from dist to points
bad tach
bad ground at the dist. itself.
 

civicsi1279

Seaman Apprentice
Joined
Aug 27, 2008
Messages
30
Re: resistance wire

i want to thank achris with his help. i replaced the coil and fired up. adjusted the timming a little and runs great. thank u for your patience. sorry don s for not wording the whole spark @ coil or spark from coil correctly. but it does mean same thing ***. but thank u so much achris.
 
Top