Mercruiser 140 points to electronic ignition

Can someone please direct me to a thread discussing methods of converting older Mercruiser 140 ignitions from points to electronic ignition?
I've recently purchased an 1978 Four-Winns "Marquis" with a Mercruiser 140 I/O and would like make some improvments to it.
Any suggestions are very welcome as this is my firs boat. My plans are to get it ready for spring so that my 9 grandchildren, children, wife and I can have some summer fun tubing and skiing on Lake Erie next year.
Thanks!
Dave

Re: Mercruiser 140 points to electronic ignition

Ayuh,.......

Do a Search of Pertronics.......

Here's a few,.....

Re: Mercruiser 140 points to electronic ignition

Hello Aerospot;

I converted my 140 I/O to electronic ignition this summer and it made a big difference in the performance. It is very, very easy, just remove the points, install the new ignition parts. You can get the parts right on the iboats site. Cost about $120.00 and worth the money and time. Should take about 30min to complete.

Good Luck;

Antmands

Re: Mercruiser 140 points to electronic ignition

The problems I see with aftermarket ignition are:

the cost

when it breaks what do you do on a weekend

and you can always spend $120.00 and replace it again.


And I don't see a performance gain.

You can put points,condenser and rotor in that distributor each spring for
about $20.00 And not have a problem YOU can't fix until next year,as far as ignition goes.

DHP

maybe we just feel we want to do something even when it does not to be done.sort of .... fix it til it's broke

Re: Mercruiser 140 points to electronic ignition

The problem i have seen is that how many Orginal 1978 distributors are in good shape


But i have been installing electronoic ingitions on motorcycles going back to 1976 and found them to perform It is really nothing new



Tommays

Re: Mercruiser 140 points to electronic ignition

easiest way is to convert it to the delco EST.
merc used it for some years and the shift interrupt is easy to rewire using the correct merc manual.
then its very easy to service and parts are locally obtainable.
however, kept in decent tune points worked well for years and years.

Re: Mercruiser 140 points to electronic ignition

kept in decent tune points worked well for years and years.

Click to expand...

Yea, but it's that "Tinkering" time of year

Re: Mercruiser 140 points to electronic ignition

Thanks to all.

I have done a search of the threads on this subject and am more confused than when I started.

Assuming that with autos, my boat would perform better with electronic spark, this seems to be true. However, it is a dependability issue with when and where I will be when the electronic ignition dies.

Where points will suffer in performance I wonder how much and if it will be that noticeable. An extra set can be kept in the boat along with a feeler gauge and screw driver for changing them if I would need to while away from the dock.

I will be on Lake Erie for most the time. To keep an extra electronic ignition module with tools to change it under the same conditions seems a bit costly for me.

I may change my opinion after next season as it will be my first with this boat. It is an 18' Four Winns Bow Rider Mercruiser 140 I/O. I hope to enjoy some family time skiing and tubing when conditions permit.

Dave

Re: Mercruiser 140 points to electronic ignition

Go with the Pertronix unit. Everyone's always concerned about things breaking down on the water when they change to electronic ignition. With the pertronix it is easy to swap out back to points - if necessary.

But let's be honest - how many times do you anticipate having to do that? Get Sea Tow - or some other towing service / insurance. Get on the radio if you break down and get towed back in!

But... as I said, you can always keep a set of points in a ziplock bag if that makes you feel better.

Re: Mercruiser 140 points to electronic ignition

well aerospot, i'm a canidate for elctronic ign. too. i ain't up for it. my engine, and i think yers too, are engines that ain't got to many mods to be doing to it. and anything ya do, ya ain't gonna notice. i know a lot of folks want to upgrade their stuff. i was taught that engines are designed as a package, ya mod one thing, ya effect another. i replace my points once a year. dwell, and time it. done......starts everytime, does wot everytime......ya can't want much more that that.

Yea, but it's that "Tinkering" time of year

Click to expand...

that's probably true. but if it is. and i had a new to me boat. i think i'd be trying to make sure eveything is as close to oem as possible for a first try at making my boat reliable, not moding it. i'd be more worried about the rubber than the points, especially the impeller......just my opionion of corse......

Re: Mercruiser 140 points to electronic ignition

OK. i'll bite. i have a merc 120-140hp. why should i do this to my boat? just looking for the advantages or dissadvantage if there are any? i don't know a lot about electronic ignitions. thx in advance.

Re: Mercruiser 140 points to electronic ignition

ok
think of what the petronix is.
its a switch.
nothing more nothing less.
hey, what are points?
they are just a switch.
all the do is turn the primary coil current on and off.
now the EST system actually controls timing advance.
and the EST system actually has the advantage because it was used as an OEM system.
myself I would just maintain the points and use the extra money for cool refreshing beverages.

Re: Mercruiser 140 points to electronic ignition

I bought the Pertronix system and have no regrets. You also get rid of the ballast resistor and run a full 12 volts. There is also a Hot spark system available and the cost for that is only around $40, which is cheaper than the Pertronix. I will get a Hot spark unit and keep it for a spare incase of failure. I can change my electronic ignition much faster on the water than you can replace and set your points. My engine idles smooth and runs great. Those people who knock these systems do so because they probably have never tried them.

Have a great day,

Rob.

Re: Mercruiser 140 points to electronic ignition

I am not knocking anything. points work and worked well for 50 years or more. the petronix is simply a switch just like points.
petronix wont make the spark any "hotter" per se.
secondary coil voltage is mostly determined by the plug wires,plugs and the gap along with combustion pressures.
if ya dont believe it use a Kv tester.
so ya just bought a 60 Kv super duper cash collector setup. odds are high the firing voltage will still be in the 5-9 Kv range unless other factors are taken in.
the advantage of the petronix system is simply less maint, it either works or its broke.
the advantage of the EST setup is no more mechanical timing advance as the module now controls timing at all speeds.
if decently maintained, I have never seen an on water failure of a point type ign system.
most all the boats I see with failures are poorly maintained rigs.
if you wait until it breaks its now a corrective action. corrective actions are invariably more expensive than preventative maint actions.
I ran a 1970 olds w-30 for to many years shifting at 6500,7200 if a beverage may be involved, with a single point set distributor. granted I did chnge to a 40oz contact spring, however most boats never see much above 4500 so the extra tension is a drawback not a help.
so no I am not knocking electronic ign, I love the simplicity and ease of maint with them, same as the advantage of EFI over a carb.
I do question the reason to spend the money if not nessasary. money would be better spent,or saved, for important things like manifold/riser maint and cooling system maint.
last 9 engines I replaced died of overheat or riser failure.

Re: Mercruiser 140 points to electronic ignition

I agree with Rodbolt. You probably won't see a performance spike. However, if it were me, I'd probably do it, just for grins. There is nothing wrong with points, as long as you understand them and understand the set up, including dwell. They are quite reliable. So are the electronic versions. Your call.

I also agree with others, that money is probably better spent on doing some basic I/O maintenance, as follows.


1. Water pump.

2. Gear lube.

3. Probably exhaust riser, maybe a manifold.

4. Pull the drive and address the Gimbal and perform an alignment.

None of the above are real expensive other than maybe the manifold and riser.

Re: Mercruiser 140 points to electronic ignition

Not to beat a dead horse here... but I agree whole heartedly about not seeing a difference in performance, simply one of maintenance. The problem with points on a boat is that people tend to not use a boat for extended periods of time. Over that time points can, and do, get corroded, etc and the result is an engine that is hard to start - if it does at all. With the electronic ignition, that is simply one less thing to worry about.

Re: Mercruiser 140 points to electronic ignition

I disagree with the performance. I have read numerous times at a different forum that idle is improved, and the engine runs better and smoother. I have nothing to compare it to because I never ran this engine with points, they were the first thing that I threw out when I bought the boat. I remember points being a pain in the ***** with my old pick-up many years ago so they were the first thing that went into the trash, along with the ballast resistor.

Now for ignition energy. I run battery voltage to my coil and my electronic ignition module. With a points ignition you are running about 9.6 volts. However when the engine is being started, the coil sees a full 12 volts to get a hotter spark for easier starting. So if I am running a full 12 volts with my electronic system, wouldn't it make sense that I am also getting a stronger spark? May also try setting the plug gap a bit wider to take advantage of this.

Have a great day,

Rob.

Re: Mercruiser 140 points to electronic ignition

Most people tend to move to the pertronix when the points are starting to fail. Then you would see a performance difference. But compare the performance of NEW points & condenser set properly and the Pertronix, and you aren't going to see any difference at all.
No reason for you to get stronger spark, unless the points are bad. As rodbolt said earlier, they are both an on/off switch, and the Pertroniz is not an amplifier.

Re: Mercruiser 140 points to electronic ignition

Yes Don it is an on/off switch with a proxemity sensor. But it is capable of switching battery voltage, not something that has been reduced to 9.6 v, so wouldn't that result in a stronger spark??

Have a great day,

Rob.

Re: Mercruiser 140 points to electronic ignition

only 2 things lazier than me, fish and lectricity.
its why I understand them .
if the conditions require 5Kv to arc the plug gap thats all you will ever see, regaurdless.
as the parts age occasionally you will see secondary voltages of maybe 12 KV on that 140.
point type systems generally are comfortable with up to 20-25 KV.

but if I was going to convert from points to electronic I would have to also eliminate the mechanical advance.
the only reason the voltage is reduced is to prolong point contact life. some point/electronic systems acutally triggered the coil with 2.5 V to the points.
now its mostly transitor triggers taking place of points.
but if ya dont mind doing the maint, points work well.