Author Topic: install electronic ignition kit in a Mercruiser 120 engine?  (Read 64843 times)

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Offline Jason

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Re: install electronic ignition kit in a Mercruiser 120 engine?
« Reply #40 on: September 23, 2013, 10:10:05 PM »
VERY cool radios!
Jason S.
1974 Glastron Carlson CV16SS 140 I/O
1986 Glastron Carlson CV23 260 I/O

Offline Neutron68

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Re: install electronic ignition kit in a Mercruiser 120 engine?
« Reply #41 on: September 23, 2013, 10:34:12 PM »
I have a 1938 Zenith 12-tube floor model almost identical to the last one you have pictured.  
I first saw one at the Pavak Museum in St. Louis Park and decided I wanted to own one!
I bought mine already refurbished at Great Northern Antique on Bloomington Ave in South Minneapolis.

Hmmm.... So if you have a 1938 12 tube model that's similar to my 9 tube model 9-S-262 then it's either going to be a 12-S-265 or a 12-S-267, pictured below respectively. Neither are mine but I wish they were part of my collection. I really liked those models. They are quite collectible and can be pricey if already refurbished/restored. I bet you paid over 1k for it.

I just looked up the bill of sale:  12-S-265, $775 in 1995
It looks just like the first one you pictured.
1978 Glastron SSV-177, Mercruiser 140

Offline OleRed

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Re: install electronic ignition kit in a Mercruiser 120 engine?
« Reply #42 on: September 23, 2013, 10:43:17 PM »
Realy Nice old radio's Rich
it suprize's me that such a young fellow in the boat world has such an interest, that's just too cool.
I grew up in a town in south east Ok. about 2500 population then, just a bit more now, we lived 5 1/5 miles south west of Antlers, Ok. My grandpa traded a battery powered electric fence charger my dad gave him for an old battery powered raidio, that was in 1959 it was not quite as big and pretty as the one's you have, but the battery was about 2ft tall by about 6 or 8" kinda square looking, and an extra battery was stored inside the radio, got no idea what kind it was, but it just had one dial in the middle kinda near the top.  It was His radio, and no one else could turn it on, he was always worried about how long the battery would last, but every night, just after dark, he had grandma mix him up a hot toddy, half a glass of corn, and the rest hot water, with a spoon full of sugar, and he listened to Herbert Armstrong.
However ... om Saturday night, he did tune in into clear channel 650 Nashville Tenn. and we got to listen to the grand ole opry, good memories.
We got electricity pulled in a little after that, had a light in both rooms, and dad bought a tv, quite a deal, several people around the area would come to watch it, and Saturday nights was the "wraslin" and one family drove a wagon and team of horses over every sat night with a coal oil lantern on a pole stuck up the front side of the wagon, Gene loved to watch wraslin, he was a scraper, he and grandma would carry on like they was in the ring, grandpa would laugh out loud at her and Gene carrying on and telling them it was fake for tv, but we didn't care, it was all fun.
Thanks Rich for the memories.
1980 23ft Scimitar

Offline Rich_V174SS

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Re: install electronic ignition kit in a Mercruiser 120 engine?
« Reply #43 on: September 24, 2013, 06:53:17 AM »
Thanks Red. I've got one "farm" radio in my collection that would interest you. Sitting on my cluttered work bench is a 1935 Philco "Tombstone" that runs on a 6 volt car or tractor battery, which would have been the norm for extreme rural areas. I haven't used it in a while but it does work. It's interesting how they work by using a vibrating tuning fork to attenuate the incoming DC voltage and step it up with a transformer to about 130 volts to power the plates in the tubes. When it's on you can hear the vibrator humming away inside the set. I don't use this radio much, for one my 6 volt car battery had died some years ago and two, some of the tubes for this set are expensive because of the time period and rarity.
« Last Edit: September 24, 2013, 06:55:25 AM by Rich_V174SS »
1967 V174 Crestflite SuperSport Modified
1987 Mercruiser 190 3.7LX/Alpha One

1970 V176 Swinger
1983 Mercury 115

Offline Neutron68

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Re: install electronic ignition kit in a Mercruiser 120 engine?
« Reply #44 on: September 24, 2013, 10:12:54 AM »
Ordered a kit for $75 off Ebay:
http://www.ebay.com/itm/1146A-Ignitor-Solid-State-Ignition-for-Mercruiser-110-120-140-165-170-180-190-/380376817756

Other questions that came to mind:

1. what "knob" do you turn to adjust the timing?
2. is there a source for inexpensive (or free) Mercruiser service manuals (paper or PDF scan on CD), that cover the 1978 Mercruiser 120?
1978 Glastron SSV-177, Mercruiser 140

Offline Rich_V174SS

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Re: install electronic ignition kit in a Mercruiser 120 engine?
« Reply #45 on: September 24, 2013, 11:20:25 AM »
To adjust the timing you loosen the retaining clamp bolt that holds the distributor into the engine block and rotate the distributor one way or the other to dial in the timing. Once the timing is set retighten the retaining bolt. A timing light is needed to set the timing.
« Last Edit: September 25, 2013, 05:11:44 PM by Rich_V174SS »
1967 V174 Crestflite SuperSport Modified
1987 Mercruiser 190 3.7LX/Alpha One

1970 V176 Swinger
1983 Mercury 115

Offline Neutron68

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Re: install electronic ignition kit in a Mercruiser 120 engine?
« Reply #46 on: September 25, 2013, 11:28:44 AM »
I just found the page on timing adjustment in the online version of the Mercruiser service manual:
http://boatinfo.no/lib/mercruiser/manuals/mercruiser3.html#/236

Other online manuals found here:
http://boatinfo.no/lib/library.html

Thank you, thedeuceman!   :D
1978 Glastron SSV-177, Mercruiser 140

Offline Neutron68

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Re: install electronic ignition kit in a Mercruiser 120 engine?
« Reply #47 on: October 03, 2013, 09:05:10 AM »
I don't see an ignition coil ballast resistor shown on the wiring diagram for Mercruiser 120 engines in my serial number range, so I suspect there isn't an external resistor.
see http://boatinfo.no/lib/mercruiser/manuals/mercruiser1.html#/308

IF there is a ignition coil ballast resistor, what is it's likely location on the engine?

I've ordered all the pieces and parts needed to make the swap:  Pertronix kit, new distributor cap, new rotor, new spark plug wire kit, new spark plugs, spark plug socket wrench, borrowed timing light.

Do I need anything else?  Any other special tools?
« Last Edit: October 03, 2013, 10:06:32 AM by Neutron68 »
1978 Glastron SSV-177, Mercruiser 140

Offline 75starflight

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Re: install electronic ignition kit in a Mercruiser 120 engine?
« Reply #48 on: October 03, 2013, 11:08:50 AM »
The wire that goes to the coil is a resistance wire, acts the same as a resistor.
1975 v-179 starflite

Offline Rich_V174SS

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Re: install electronic ignition kit in a Mercruiser 120 engine?
« Reply #49 on: October 03, 2013, 11:21:33 AM »
Correct, instead of a ballast resistor you have a resistance wire. When connecting ther Pertronix you need to connect the red wire at a point in the circuit before the resistance wire.
1967 V174 Crestflite SuperSport Modified
1987 Mercruiser 190 3.7LX/Alpha One

1970 V176 Swinger
1983 Mercury 115

Offline Neutron68

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Re: install electronic ignition kit in a Mercruiser 120 engine?
« Reply #50 on: October 03, 2013, 11:23:32 AM »
The wire that goes to the coil is a resistance wire, acts the same as a resistor.

It that is the case, then I'd need to find the beginning of that wire, so I could connect the +12V wire of the electronic ignition module to +12V before the resistance wire. 
Any idea how long it is, and if it's visually identifiable as a resistance wire?
1978 Glastron SSV-177, Mercruiser 140

Offline 75starflight

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Re: install electronic ignition kit in a Mercruiser 120 engine?
« Reply #51 on: October 03, 2013, 11:49:44 AM »
Correct, instead of a ballast resistor you have a resistance wire. When connecting ther Pertronix you need to connect the red wire at a point in the circuit before the resistance wire.

Actually mine is hooked right at the positive side of the coil, I have not had any issues with it.
1975 v-179 starflite

Offline Neutron68

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Re: install electronic ignition kit in a Mercruiser 120 engine?
« Reply #52 on: October 03, 2013, 12:20:44 PM »
Connecting right to the bolts on the ignition coil would certainly be easier.  
I was just going on what Rich has said in this thread.
Quote
Rich_V174SS:  Also, it may work better to wire the positive lead of the Pertronix to a point in the ignition circuit before the ballast resistor instead of to the positive terminal of the coil otherwise you may lose power if you operate your trim while the engine is running.
Quote
Rich_V174SS:  Looking at your engine pic you posted recently I see you don't have an electric choke but you can still wire the positive red wire from the Pertronix to the front side of your ballast resistor, not the back side that goes to the coil.
Quote
Rich_V174SS:  When connecting ther Pertronix you need to connect the red wire at a point in the circuit before the resistance wire.
« Last Edit: October 03, 2013, 01:58:40 PM by Neutron68 »
1978 Glastron SSV-177, Mercruiser 140

Offline 75starflight

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Re: install electronic ignition kit in a Mercruiser 120 engine?
« Reply #53 on: October 03, 2013, 02:13:58 PM »
Correct me if I am wrong Rich, but doesn't the resistance wire just cut the volts back to 12 from the 13.5 that the alternator puts out?
1975 v-179 starflite

Offline Rich_V174SS

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Re: install electronic ignition kit in a Mercruiser 120 engine?
« Reply #54 on: October 03, 2013, 02:21:59 PM »
The is correct, and running the Pertronix connected to the coil would not be a problem, the engine will still run fine. But when you start using accessories or the trim the voltage required for the Pertronix may drop below the threshold needed to keep it running. I had this problem with mine so I chose to connect it before the resistance wire and haven't had any more problems.
1967 V174 Crestflite SuperSport Modified
1987 Mercruiser 190 3.7LX/Alpha One

1970 V176 Swinger
1983 Mercury 115

Offline Neutron68

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Re: install electronic ignition kit in a Mercruiser 120 engine?
« Reply #55 on: October 03, 2013, 03:28:13 PM »
I found a Mercruiser 120 side view on photobucket (its not mine and I've no idea what the black arrow is indicating).

Can someone point out:
1. the resistance wire and
2. a good place to connect the Pertronix +12 wire

1978 Glastron SSV-177, Mercruiser 140

Offline Rich_V174SS

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Re: install electronic ignition kit in a Mercruiser 120 engine?
« Reply #56 on: October 03, 2013, 04:29:11 PM »
That's not a great pic to make out specific wires. There should currently be two wires on the positive terminal of the ignition coil, one purple and the other purple/yellow. The plain purple one is the resistance wire, the one with the yellow stripe is a bypass that goes to a terminal on the starter solenoid. The resistance wire ties into the purple wire that goes to the alternator and (if you had one) the electric choke, the connection may be hidden within the harness wrap. This line becomes live when the keyswitch is turned on. The purple/yellow wire (bypass) is only active when cranking the engine to provide a boost to the coil by bypassing the resistance wire.

The black circle with arrow is indicating either a switch or terminal block for wires that are not relevant to our situation.

Here's a Mercruiser 120 wiring diagram I found, not the most clear but it's all I have. The dotted line indicates the resistance wire.
« Last Edit: October 03, 2013, 04:40:35 PM by Rich_V174SS »
1967 V174 Crestflite SuperSport Modified
1987 Mercruiser 190 3.7LX/Alpha One

1970 V176 Swinger
1983 Mercury 115

Offline Neutron68

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Re: install electronic ignition kit in a Mercruiser 120 engine?
« Reply #57 on: October 03, 2013, 04:46:33 PM »
I believe this is the correct wiring diagram for my engine.  
It has a 40A circuit breaker rather than a fuse:
http://boatinfo.no/lib/mercruiser/manuals/mercruiser1.html#/308

In terms of a pre-resistor place to connect to 12V,  how about:
1. at the 40A circuit breaker or
2. a 12V connection point at the starter solenoid?

« Last Edit: October 03, 2013, 05:04:17 PM by Neutron68 »
1978 Glastron SSV-177, Mercruiser 140

Offline Rich_V174SS

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Re: install electronic ignition kit in a Mercruiser 120 engine?
« Reply #58 on: October 03, 2013, 04:49:53 PM »
Those would be live all the time so if you connected to either of those locations you wouldn't be able to shut off the engine. The purple wire going to the alternator would be the most viable location you can tap into, or strip back some of the wrap near the main harness plug and tap into the purple wire there. That line is controlled by the keyswitch, on and off.
1967 V174 Crestflite SuperSport Modified
1987 Mercruiser 190 3.7LX/Alpha One

1970 V176 Swinger
1983 Mercury 115

Offline Rich_V174SS

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Re: install electronic ignition kit in a Mercruiser 120 engine?
« Reply #59 on: October 03, 2013, 04:58:59 PM »
Actually, lemme rephrase that:

If you connected the Pertonix to those locations you mentioned then the sensor module would be live all the time, even without the engine running. The coil would still be controlled by the keyswitch but there would be nothing to turn off the Pertronix module.
1967 V174 Crestflite SuperSport Modified
1987 Mercruiser 190 3.7LX/Alpha One

1970 V176 Swinger
1983 Mercury 115