4.5 merc ignition troubleshooting... seloc manual seems to be wrong

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Seaman
Joined
Sep 8, 2008
Messages
57
I have a '79 4.5, also known as the model 45, and it runs intermittently... upon checking the system, it gets spark sometimes, but then it goes away.

the kill wire has been completley removed from the coil, so its not an issue.... my system is the type II, WITH the module

I do have the seloc manual for the 4.5, but it is calling out different wire colors than my motor has, and the testing procedure jumps around from the NON module ignition to the ignition WITH a nodule... its very unclear about what to test or how to test it, and frankly, with the manual as screwy as it is in that section, I dont trust the parts of it that I think I might understand....
and its calling for red and blue stator coils, whereas mine are black and white.....

I have seen pictures of other peoples 4.5 mercs online, and they all look like mine does, which IS different then the seloc manual shows... maybe it was written using a foreign merc engine as the model, but that doesnt help us with the american version of the 4.5

can someone help clarify how I should proceed in my attempt to find the intermittent short or disconnect in this system?

I have already tested for continuity and shorts in the basic wiring, and its all in good condition

I need to know how to test the module (and diodes)... the stator coils... and the condenser.. and what values are acceptable in the test. I have already replaced the spark plug coil with a new one in my attempt to make the engine run.
Thanks
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
50,295
not much difference from the 3.7hp to 6hp mercs

all the same parts, slightly different carb
 

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Seaman
Joined
Sep 8, 2008
Messages
57
not much difference from the 3.7hp to 6hp mercs

all the same parts, slightly different carb
the ignitions look much different on both the 3.7 and the 6hp motors vs the 4.5, according to all the books and internet photos I've seen... Ive tried to go that route in an attempt to find SOMETHING i could use to figure this out, but have had no luck.... and apparently no one else has either :-(
 

Mohawkmtrs

Chief Petty Officer
Joined
Jan 13, 2010
Messages
563
According to your serial number, you have the alternator-driven ignition with the 336-4516 Phase-Maker ignition.

Go to cdielectronics.com, look up your ignition system in their troubleshooting guide.
 

centerline

Seaman
Joined
Sep 8, 2008
Messages
57
According to your serial number, you have the alternator-driven ignition with the 336-4516 Phase-Maker ignition.

Go to cdielectronics.com, look up your ignition system in their troubleshooting guide.
ill check it out.. thank you.
 
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