Mercruiser 165 Straight 6- Trouble starting.

[4327]

I just picked up a Glastron with a Mercruiser 165 Straight 6.
Approximately 1977
Power at Positive side of coil is 5.9VDC.
From reading in the forums I see that this is correct.
Coil tests within OEM specs.
The only way I can get it to start is to jumper a 12VDC current direct from the battery.
Also I have to remove the jumper to shut it down.
Forums also state that there should probably be a 12VDC source that produces current on "START" position only.
The wiring diagram I have shows only 1 conductor going to the + side of the coil and some diagrams show a resisitance wire but there seems to be differing opinions on that wire as well.
Maybe I have the wrong diagram?
Where do I go from here?
Thanks

 

[Scott Danforth]

start cleaning electrical connections

also, file and service the points

plenty of stickies on servicing and troubleshooting point type ignition.

 

[alldodge]

The wiring diagram I have shows only 1 conductor going to the + side of the coil and some diagrams show a resisitance wire but there seems to be differing opinions on that wire as well.
Maybe I have the wrong diagram?

You need 2 wires going to the coil on + side and 3 on the - side. There may only be 2 on the - side if the brown wire is tied together inside the harness. Don't bother with the - side right now.

Here is the wiring diagrams

 

[4327]

Thanks Alldodge. Can you give me more info on the #5 White resistance wire? I don't think I am quite grasping that part

 

[4327]

Scott...What are stickies and where do I find them? I'm new here.

 

[Bondo]

Scott...What are stickies and where do I find them? I'm new here.

Ayuh,..... Welcome Aboard,.... At the top of any of the I/O forums, or the Don'S Adults Only Section link in my signature,.....

 

[alldodge]

Thanks Alldodge. Can you give me more info on the #5 White resistance wire? I don't think I am quite grasping that part

The white resistance wire comes directly from the key switch, same as purple wire in todays motors. You should also have one coming from the starter (Tan) which supplies full 12V for starting. With it not running without a jumper, sounds like your missing both or bad connections on both. Check your connections

 

[4327]

I will try that today.
Just so we are clear here...It runs without the jumper but will not start without the jumper.
Does that narrow it down any?

 

[kenny nunez]

Follow the path of the tan wire to the starter solenoid. With a test light or volt meter on the “R” terminal is a good place to check. Most times the solenoid is where the problem is. Over time the contacts become corroded in the solenoid. If you replace the solenoid be sure to get a new one and not a rebuilt, sometimes they are defective.

 

[4327]

Thenks Kenner...will do

 

[alldodge]

I will try that today.
Just so we are clear here...It runs without the jumper but will not start without the jumper.
Does that narrow it down any?

Yes, and KN has your answer