If I were a 1986 Merc resistor wire where would I be???
 

I cannot seem to find info on this resistor wire thing and where that wire might be located...??

Anyone have a clue??

Follow the positive coil wire back trough the harness.

You probably don't have one. Their only used on the old "points" type ignition. Positive side of coil would have 2 wires. One Purple/Yelo which goes to the starter solenoid. The other would be Purple which goes to the ignition switch and alternator. It would be the section of wire that runs from the coil positive to where it splits to go to the alternator and ignition switch which would be with in the engine harness itself. The wire is stainless steel, not copper. But as I said unless you have a points type distributor you won't have one. 1986, doubt it. What seens to be your problem?

The engines had points when they were in Baja, I converted 4 years ago to electronic merc stuff old square boxes, since then I been fighting on and off ignition issues that never seem to clear up, 4 years of every other possible issue I am finally focused on this now that the engines and SAME engine harnesses are in a different boat, I always thought it was due to wiring issues in the Baja... problem followed engine...

One runs fine and always has, other almost never goes over 4500, but once in a whikle it will hit and match the other at 4900-5000

I never knew about a resistor wire until 2 weeks ago and now I am looking into it, one day I have 7 volts at coil, other days I can see 12 or so, 14 if running..

I have replaced every part possible over time and this is the only thing that makes sense now...

I purchased 2 internal resisted MSD coils today from Summit, gonna cut resistor out if I find it, if not I will run my own power wire and see what happens, if that does not clear it up I am ditching all ignition and wiring and building my own harness and aftermarket ignition system....

I know its NOT....

ign. control box
dist. P/U
ign. switch
Fuel press.
fuel flow
carb
valve springs or any oither engine issue..
timing
airflow to hatch area
prop

So yes I have covered my bases....LOL

talking to a few guys after and we seem to think my solution should fix it... sure would be nice!!

Why the other engine has not given me issues I have no clue.... but I cant see it being anything else at this point....

I would just get a new engine wiring harness and be done with it. It's 26 year old wiring anyhow.

Could be a bad connection somewhere in the purple wire in the engine harness. Cut open the harness between the coil and alternator and follow it from there. If this is a harness from an engine which had a points type ignition than it will be the wire from the coil positive to where it splits and runs purple wires to the alternator and to the 10 pin plug which in turn continues to the ignition. Cut it out and replace with regular wire. If you have a Purple/Yelo wire running from the coil positive to the starter solenoid it is no longer needed. It originally supplied a full 12v to the coil during cranking only with the points type ignition. After starting a reduced voltage was supplied to the coil through the resister wire.
Check your PM box.

I know these problems will make you want to beat the engine hatch against your head.If it is a never before heard of mystery problem I will have it with boat . car and god forbid an Airplane , that is why I am back into sailing.

Why can.t you wire the coil hot direct from the battery and run it and see if the problem still exists? Can the coil have 12 volts or does it need the resistance if it does wire a resistor inand jump the harness and go right from the battery with it.

fixx
 

its the white wire, the coil wire + all you really need to do is hook up a relay to give you a full 12 volts

I am sure they are hard enough to find and from what I hear if I do find one they are 300+ dollars, I will run my own power and call it a day!!