electronic conversion

SHickey

Petty Officer 1st Class
Joined
Apr 29, 2011
Messages
263
Hello,

I have what I believe is a dead coil in my '74 StarCraft American 20 that has an almost vintage 165 Mercrusier straight six motor with a MC-1 outdrive. The boat had run fine all season so far and today it began stuttering while I was slowly cruising in the NYS Barge Canal. I got her back to the ramp and when I got her home she ran well in the driveway and just petered out like she was out of fuel. I pulled a sparkplug and noticed after a couple of cranks the spark was hardly noticeable and then no spark at all after a few more cranks.

I'm thinking of replacing the coil and points with an electronic system instead and was wondering what brand would be suitable for this type of application. I'm not a genius when it comes electronics and electrical systems but I do have a very knowledgeable neighbor that could help me if I get stuck. I believe a marine coil would run me @ $75 and the electronic ignition would cost me more but it would eliminate the need for point adjustment and trouble shooting if my motor isn't running right.

Any thoughts and advice would be most welcome and vendor recommendations would help too.

Thanks and safe boating!!
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
My belief, and experience, is that changing points to electronic is one of the simplest and best ways to improve any engine. When I have my 165, I built my own CDI system. The engine started and ran so much better....

So, I'm not expecting you'll build your own, so the one that seems to get the best press here is Petronix... The module (I believe is a 91163A) replaces the points, and using their 3ohm coil compliments it... There is a bit of a wiring mod to do on the engine, you need to supply full 12 volts to the coil +, which means finding a switched 12v source. The existing wires on the coil + are, one from the starter motor (can be removed completely), and the coil end of the 'resistor wire'. It looks just like a normal wire, but it's not...

Cheers,

Chris...........
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,343
ign coils do not cost that much .I disagree with achris on the electronics. electronics are a "on=off" system . They work or they dont.
points and condensor sometimes will give you a warning that something is up and no system will protect you against a coil going south
 

Rick Stephens

Admiral
Joined
Aug 13, 2013
Messages
6,118
I went with the little bit higher tech full electronic Delco Voyager EST ignition when my spendy Thunderbolt IV gave up the ghost. I couldn't be happier. The replacement control module for the end of life Thunderbolt IV costs more than the EST. So I counted it penny wise. Several years later, it has been trouble free - in fact, attention free. I never even think about it or need to work on it.
 

SHickey

Petty Officer 1st Class
Joined
Apr 29, 2011
Messages
263
Thank you all for your responses, I believe I will go with the Petronix system Achris recommended and see what happens It will probably be a selling point when I decide to sell my boat sometime in the future and will take most of the guesswork out of ignitions irregularities or complete failures. If that makes sense??
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
50,224
sounds like the condenser is going out.

service the points/condenser, go boating.
 
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