Mercury model 40

[Tubs]

I do what seakaye12 suggest but use a 3/8-Inch
Drive Ratcheting Breaker Bar Adapter on smaller
motors. (eBay) I have been using the one in this
video for several years. The selector for reversing
direction is frozen but how many motors run
counterclockwise?
Video Link – https://youtu.be/ZlRJQIm_99A?si=tUYJrU5cFKZgIBm7
Tubs
.

A "Boathouse Repair" is one that done without having tools or the skills to do it properly.

[crosbyman]

20kv….so you were talking  coil to plugs ???

what model of 4hp is it ?

because the firing  voltage from the stator  to the  ignition coils themselves   surely can’t  be  20KV !   maybe 400v  with  phase maker ignition.

 

see AOMCI  western region article

https://wrcoutboards.org/wp-content/uploads/2021/02/The-Phase-Maker-CDI.pdf

MERCURY Outboard no SPARK easy and CHEAP repair! (youtube.com)

Magazine Articles | Western Reserve Chapter (wrcoutboards.org)

Joining AOMCI has priviledges 🙂

[seagull764]

Thanks again , and your right I was going by the thickness of the wire coating 400 v seams more accurate, all modern automotive wire is rated at 600 v sand one layer of electrical is rated at 600 v for ac use

the articales you provided are very interesting.

i have 3 of these 71 or 73 motors and i thought i could make one out of 3 , but I keep running into new problems  are there any aftermarket coils that will work , if i go by the part number they are 160 ea

[crosbyman]

coil wise I can’t say  if  you could swap in non Merc coils… Maybe Dave Bernard would know ??  the problem may be more  physical  to fit them under the cowl

 

wire wise  I would not worry to much about jump over  with 400 V

 

in the video the guy rebuilds the wires with new  crimps at the ends  and some  heat shrink on the crimps

Joining AOMCI has priviledges 🙂

[seakaye12]

seagull764 wrote:

i have 3 of these 71 or 73 motors and i thought i could make one out of 3 , but I keep running into new problems are there any aftermarket coils that will work , if i go by the part number they are 160 ea

 

The other path to take is to swap out the ignition back to the magneto with points and condensor.  If one of your motors has that system….explore what would be involved to swap the entire system out. 

[jeff-register]

Coat it with Super Corona dope, good for 4500 volt Can be had at MG chemicals. Clear insulating coating on line.

[seagull764]

By aftermarket coils , I meant later model years , on one blog I read that only the green red or orange ones would work in that motor , the black ones look identical and are really cheap.
all 3 of the ones I have are op,en between the coil and the. Plug

ive found several badly corroded wires and replaces them I chose 14 ga wire not knowing the current or voltage drop

thanks for all the great advice

[crosbyman]

coil wise  the open  condition may be limited to the boot end connection.

 

I would not  dump those  coils rightaway.    if the boot end is the problem you may be able to replace the boot by sniping the old ones off adding new boots/springs  if the HV  wire lenght permits  clipping half an inch off……. right behing the boot collar.

see this OMC  ignition…trouble guide …not yours I know…. but the end plug problems  may be  same as your Merc boots on those suspected bad  coils.

if you  retest the coil with the old boot snipped away you  may find the secondary resistance is no longer open. 🙂

 

as to the 14 ga. wires  you installed I would not worry about ” voltage drop”   on 12 inches of wire.

Joining AOMCI has priviledges 🙂

[seagull764]

I’ve taken the plug wires out and tested at the coil itself , still no luck

[Author]

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