Pertronix Ignitor OMC ESA "Fix"

newport dave · Mar 20, 2005

I have a customer who wants to install a Pertronix Ignitor conversion on an '88 OMC 7.5 / King Cobra and will need to use the "fix" suggested by Pertronix for use with the OMC Electronic Shift Assist. I know that it has been discussed here many times, but can anyone share how they actually constructed it? Did you use a little circuit board and enclosure or what? Pictures would be good! Dave

olbuddyjack · Mar 21, 2005

Re: Pertronix Ignitor OMC ESA "Fix"

I soldered the leads as required and insulated them with heat shrink tubing. Then I put the whole thing in a big diameter piece of heat shrink to hold it all together. I'll post a pic as soon as i can take one.

lakelivin · Mar 21, 2005

Re: Pertronix Ignitor OMC ESA "Fix"

I've heard of people using a small plastic box purchased at Radio Shack (along with the rest of the parts) to construct the workaround. But haven't seen it myself, maybe someone else has done it this way & has pics?

16Pilot · Mar 21, 2005

Re: Pertronix Ignitor OMC ESA "Fix"

I still cannot find a pertronix for my 4.3 omc? help I tried to find that catalog that someone showed but I could not pull it up. Does it really make a difference?

Dunaruna · Mar 21, 2005

Re: Pertronix Ignitor OMC ESA "Fix"

Try here http://www.go2marine.com/g2m/action...tronic_ignition_conversion_kit_pertronix.html Does it make a difference? Well, most will say yes, elec ignition switches more efficently so the coil delivers a stronger spark - that then leads to better combustion, easier starting, more economical etc,etc..... It also varies the dwell according to load and RPM thus maximising timing settings. Its a little computer for your ignition! The down side is that if the module fails, your stuck. Can't fix it on the fly. Most people carry their old points/condenser/screws so that they can retrofit in an emergency. Aldo

16Pilot · Mar 21, 2005

Re: Pertronix Ignitor OMC ESA "Fix"

is it safe to use a coil with 40,000 on a standard motor? would that not kill the plugs?

JasonB · Mar 21, 2005

Re: Pertronix Ignitor OMC ESA "Fix"

I use the 40k volt coil on my 302 and it seems to be ok on the plugs, but I change them every 2 years anyway.

Dunaruna · Mar 21, 2005

Re: Pertronix Ignitor OMC ESA "Fix"

The coil works on a 'supply and demand' principle. A 28 thou plug gap will never be able to utilise the 40,000v coil, the spark required to jump 28 thou isn't very strong - the coil doesn't have to work hard to do it. It's a different story with modern high energy systems, the plug gaps are often 40+ thou, you need the high energy coil to jump the gap and complete the curcuit. That being said, a strong and sharper plug fire is better than a weak one. If you need to replace your plugs more regularly then it's a small price to pay for a better bang. Aldo

trog100 · Mar 21, 2005

Re: Pertronix Ignitor OMC ESA "Fix"

my 3.0 seems to pull nearly 5000 rpm at w.o.t fitted with transistor enhanced ignition and extended nose no inbuilt resistor ngk plugs set at 40 thou.. it used to run somewhere between 4700 and 4800 with just the points and standard nose plugs set at 35 thou.. i made the alteration to improve the idle and stop the plugs sooting up after prolonged periods of low speed running.. and was rather surprised at the apparent top end rpm increase.. thow perhaps i shouldnt be.. trog100

newport dave · Mar 21, 2005

Re: Pertronix Ignitor OMC ESA "Fix"

olbuddyjack, I have heard that it can get hot. Have you noticed that it gets hot? Dave

trog100 · Mar 22, 2005

Re: Pertronix Ignitor OMC ESA "Fix"

the most robust way of making such a thing would be to put it in a little open topped pastic box.. leaving the connection wires coming out the end pour in some epoxy resin in and fully encapsulate the entire thing.. the little box can be removed when the resin has set leaving a neat little resin block with wires coming out of it.. trog100

lakelivin · Mar 22, 2005

Re: Pertronix Ignitor OMC ESA "Fix"

Originally posted by trog100: the most robust way of making such a thing would be to put it in a little open topped pastic box.. leaving the connection wires coming out the end pour in some epoxy resin in and fully encapsulate the entire thing.. the little box can be removed when the resin has set leaving a neat little resin block with wires coming out of it.. trog100

Cool. I take it you coat the box with something like a light oil or vaseline to make removing the box easy?

trog100 · Mar 22, 2005

Re: Pertronix Ignitor OMC ESA "Fix"

LakeLivin.. yes or u could just make the container out of insulating tape it only needs to hold the epoxy while it goes off.. u can use this method with any piece electronic trickery if u want to make it bomb proof.. trog100

lakelivin · Mar 22, 2005

Re: Pertronix Ignitor OMC ESA "Fix"

Originally posted by trog100: .. u can use this method with any piece electronic trickery if u want to make it bomb proof.. trog100

Aren't there some things where heat might be an issue? Wonder what encasing components in epoxy would do w.r.t. temps...

trog100 · Mar 22, 2005

Re: Pertronix Ignitor OMC ESA "Fix"

perhaps "any" was the wrong word.. the method can be used in conjunction with metal heat sinks if required.. the resin probably conducts heat better than still air does.. mind u i cant see mechanical relays liking it much.. he he.. its main purpose would be to protect components against vibration or physical damage.. trog100

tommays · Mar 22, 2005

Re: Pertronix Ignitor OMC ESA "Fix"

if you look at circut boards made to live in a harsh enviroment they are normaly dipped in some type of epoxy that seals the board and componets the only down side is board level repiar becomes a non-option you cant get the stuff off without destroying it tommays

trog100 · Mar 22, 2005

Re: Pertronix Ignitor OMC ESA "Fix"

yes not overly easy to fix once encapsulated.. he he i wouldnt use a board with just a couple of diodes and resistors thats what the little box was for.. useing a small board u could just lay the pre soldered components complete with wires on top of the board and pour resin on to them.. does the same thing just not as neat as the little block with wires coming out of it.. the heatshrink tube method is okay just not quite as bomb proof.. the other option would be to build the circuit in a little case and mount it somewhere.. u can do a similar job useing silicone in a tube stuff.. it would take a couple of days to set.. but u could get it off if u really wanted to.. he he.. that would produce a rubbery little block with wires coming out of it.. that silicone in a tube stuff stands massive amounts of heat by the way once its set.. very tuff and rubbery.. almost indestructable.. easy to cut with a very sharp edge being its only weakness.. trog100

olbuddyjack · Mar 22, 2005

Re: Pertronix Ignitor OMC ESA "Fix"

newport dave,

olbuddyjack, I have heard that it can get hot. Have you noticed that it gets hot? Dave

I donno Dave, I never noticed. I'll have to check it out when it gets back in the water. It looks ok, it didn't scorch or anything.

weatherz · Mar 22, 2005

Re: Pertronix Ignitor OMC ESA "Fix"

Why in the illustration do they use two 24.7K 1/2w resistors in parrallel? Why don't they use a 12.4K 1 or 2 watt resistor? Also if you are worried about heat when covering with epoxy, just double the ratings of the components and u should be fine. i:e: 6amp diodes and (2) 1 watt resistors or (1) 2 watt resistor. [2 of the same value resistors in parrallel = 1/2 of the value in ohms, for two of differing values, always less than the smallest value. Looks to me like the diodes are just blocking diodes to isolate the coil from the shift assist since they are reverse biased and the resistors set a reference voltage for the shift assist circuit.

lakelivin · Mar 23, 2005

Re: Pertronix Ignitor OMC ESA "Fix"

Originally posted by trog100: ....u can do a similar job useing silicone in a tube stuff.. it would take a couple of days to set.. but u could get it off if u really wanted to.. he he.. that would produce a rubbery little block with wires coming out of it.. that silicone in a tube stuff stands massive amounts of heat by the way once its set.. very tuff and rubbery.. almost indestructable.. easy to cut with a very sharp edge being its only weakness.. trog100

trog, I can't give you the exact details, but I've heard from two different, knowledgable people (one an electrical engineer, the other has a PhD in, I believe, industrial chemistry) that you want to be careful with silicone caulk and electronics. Something along the lines that even fumes given off by silicone can damage or cause problems with electrical components/ connections. This came up w.r.t. sealing an outdoor control box for a septic tank pump with silicone caulk. They both recommended using something else, like plumbers putty. One, whose job is head of the county department responsible for septic system permits & inspections, said he had seen several boxes where this had been done and caused failure over time. Wish I had a bit more time, I'd do a quick google search to try to provide a reference or two.

Pertronix Ignitor OMC ESA "Fix"

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