1972 evinrude 125hp converted?

hey fellow boaters, have a 1972 125hp evinrude starflite, gave me problems all summer, got to take it out only 4 good times this summer and it only ran good 2 of those times . i guess i should say that i bought this motor early this year. only payed 300 bucks for boat and motor. hears how it worked this summer. i first pulled the carbs cleaned rebuilt and re-synced. used only 93 gas mixed 50:1. replaced fuel lines and bulb, added a water/fuel filter. it acted like it would have a mind of its own. it would run then it wouldn't run, wanted to bog out, an sometimes stall when going from idle to giving gas. sometimes it would per like a kitten, then some times it would run real rough. i went through prob. 50 spark plugs (mostly champion, but i did try autolight once to see if that would help, but it didn't) most of the time it seemed to help, for a little anyways. i have changed the fuel pump to no prevail. the last time i tried working on it myself for some reason it had no spark, the battery was a little low so i charged it, again after i charged no spark. i then was fed up with it i took it to a local boat shop. the guy told me the power pack was the problem, and probably the problem the entire summer. does this seem right? he said that the pack was expensive, he said he could replace it for 300 bucks or he said he could convert it to a point system for 200 bucks, eleminating ever having to change or worry about that pack again, just changing a 14 - 15 dollar part. does this seem like a good idea? he said the compression was great, and he thinks that the pack is the whole problem. so I'm asking all of these great mecanics here on iboats there opinion. ty so much guys, i hope to be able to enjoy next summer on the water.

Re: 1972 evinrude 125hp converted?

I can't comment on the powerpack issue but I can say to run it on good old 87 and run the OEM spec'ed Champion plugs.

Re: 1972 evinrude 125hp converted?

i only used the 93 because everyone said that those motors were designed to work off the high octane, so i was only doing as the older generation told me, lol. and yes champion seemed to work the best but the oem plug is a surface gap plug and they came out with a regular type plug to replace it alot of people told me that the surface gap plugs were not as good that they foul out alot more, ty for the input

Re: 1972 evinrude 125hp converted?

When getting into ignition problems on solid state type ignition systems, you are immediately into expensive territory. While power packs do have a higher failure rate, that does not mean that this will correct the problem if you also have a bad/weak stator or timing sensor. That engine does need to turn over at least 250 rpm when cold cranking-in order to get the ignition system to fire. A weak battery can be a problem if it cranks too slow. I've never changed back to a point system, but I would be concerned about the proper mounting location for the points and the point cam as well as the distributor cap. Your block may not be setup/machined to accept those parts. Perhaps someone else can comment regarding this issue. Those were strong running engines in their day-and worth saving if the compression is as good as you say. The one weak point to these engines are the electric shift lower units and control boxes. While not problematic, they are hard to find parts for if you have a failure.

Re: 1972 evinrude 125hp converted?

I would not be inclined to convert the motor from its present setup. You also have an amplifier, not a powerpack. I was just looking at a parts diagram on your ignition and it looks like sort of a hybrid, that has elements of the older points/distributor/amplifier system, but uses a sensor instead of points.

If the amplifier is bad, buying one from BRP is expensive. I wouldn't do that though, because rumor has it that BRP is selling rebranded aftermarket parts for the old motors anyway. You should be able to buy an amplifier from CDI for about half of the price of the "BRP version," which is probably a CDI manufactured part.

This is still going to cost you about $200 - $300, but the quality of the part is probably better than the original and you'll avoid problems associated with the conversion. I'm not going to say that the points coversion wouldn't work, but I would be very leery of it, unless the mechanic can provide references in regard to previous conversions that he has done. In short, if you can't talk to someone who had this done to his motor, I would be very reluctant to go launching off on what could be a constant problem.

I also don't see how such a conversion could be done, without costing just as much as an amplifier replacement, unless the mechanic intends to use parts off of a junk motor. That, to me, is another reason to find the suggestion to be very dubious. Outboards are kind of like computer modeling - junk in = junk out.


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Re: 1972 evinrude 125hp converted?

I have also found that poor/dirty electrical connections can cause all sorts of problems. Make sure and check all connections, including grounds, they should be clean and tight.

Re: 1972 evinrude 125hp converted?

According to the parts list I just looked at, the model 125ESL72R, 1972 125hp motor does not have an "amplifier". Neither does it have a "power pack". It has the Prestolite Pulse Pack system. No points. And I really don't think you can put points in it if you tried, because the crankshaft probably doesn't have any lobes. And yes, it should be run on high octane gas, but that isn't the problem here.

jonnymarquis, it looks like you are caught between a rock and a hard place. Probably no qualified people to work on your motor, right? I wish I could tell you what is wrong with it, but I can't without doing an orderly troubleshooting on it. Neither can anybody else. It has always been assumed "It must be the black box (pulse pack)". And often it is. But you can spend a lot of money on assumptions.

Re: 1972 evinrude 125hp converted?

FR - just for my own "edumacation," what is the difference between a pulse pack and an amplifier? This might also be of help to the OP, so that he can determine availability of a replacement part.


PS: Just did some surfing. CDI seems to make a replacement part (#113-8362) and it looks like some people use the terminology "Battery Powerpack." The price seems to run from about $270 - $370, dpending on who you buy the part from. A couple of the listings that I saw, spcifically mentioned this part as a replacement on a 1972 OMC 125hp.



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Re: 1972 evinrude 125hp converted?

I sold a 71' 125hp just this summer and it was a strong motor. Your 72' has fixed jets and should run even better. The 71' was the first year of electronic ignition and had it's share of teething issues, but if your's lasted this long I would be reluctant to switch to points. The power pack if needed is available, just google the part#. I wouldn't condemn it unless someone who has the factory manual troubleshooted it first. I sold my manual with the motor, but Searayman13 on Epay has that manual. There is a "clipper" module that is supposed to fall on it's sword before the powerpack gets zapped. I would check that first, it looks like a voltage regulator, and is mounted on top of the motor. The BRP parts site will show you what it looks like.

Re: 1972 evinrude 125hp converted?

An "amplifier" is (originally) made my Motorola and is triggered by breaker points. A "Pulse pack" was made by Prestolite, is a different shape, and is triggered by a sensor, no points. Both use that sorry distributor system.

Re: 1972 evinrude 125hp converted?

Once I looked at the diagrams closer, I was getting that the pulse pack is used with a sensor, rather than points. I was just curious about what goes on electronically.

Maybe a subject for another thread, sometime.

The good news is that it sounds like this motor can be repaired, if the OP wishes to spend the money. I hear you on the distributor system, though - it appears that whether you are talking about one with points or a sensor, the rotor is the problem, because it seems to be an NLA item across the range of motors that use it.



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Re: 1972 evinrude 125hp converted?

lol I'm still so confused, i don't want to spend that much on that pack and it not be the problem, or take the chance with that conversion. i mean he sounded confident on changing it, said he done it before. on the other hand what ever damaged the pack in the firs place may damage a new on in no time. any of the other problems that i mentioned sound like it may be fixed with this change?, I'm almost tempted to look in the paper for a newer used motor. i feel stuck.

Re: 1972 evinrude 125hp converted?

I think that what most of us are questioning, is just how this mechanic intends to convert your motor to a points system.

In the way of a quick review, prior to the various ignition systems that OMC started to use with electronic components, there were two basic systems (FR, jump in if I am missing anything) - the two cylinder motors with two sets of points, condensors and ignition coils under the flywheel and a belt driven distributor system for the four cylinder motors, with points under the flywheel.

Later on, the distributor system was redesigned and placed under the flywheel. There were two variations of this setup - one with a set of points, a distrubutor/rotor and an amplifier mounted on the starboard side of the motor, while the other had a sensor, the distributor/rotor and a pulse pack. Your motor has the latter.

A third system then entered the picture and became the basis for OMC ignition systems for many years afterwards. This system has a sensor system (timer base) and a powerpack.

The common component to all three systems, is an alternator made up of the flywheel and the stator. The alternator is what supplies the current used for both ignition and the charge system.

Where your situation comes into play, is the matter of a cam lobe. The points equipped OMC motors, no matter which version, have a cam lobe on the upper end of the crankshaft. Without the raised portion (cam) on the crank, there is nothing to open the points at the correct time. Since your motor has a sensor instead of points, there probably in no cam on its crankshaft. That begs the question - just how does this mechanic propose to install points in your motor?

I don't want to completely dismiss your mechanic, because he may know something that I don't, but I still have a strong suspicion that what he is recommending, is not a good idea. What I would do, instead, is to get my hands on an OMC manual for your motor and do the various tests of the ignition system, in order to find out exactly what is wrong with it. I am not completely familiar with pulse packs, but I do know that the later powerpacks can be adversely affected by a weak stator. If this is an issue with pulsepacks, at least you would be able to test your staor, before investing any more money in the motor.



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Re: 1972 evinrude 125hp converted?

ty, all of you guys are far more mechanically inclined then me, and it shows so when he tells me something that he can do i just nod my head and say ok, i do have an original service manual just for my specific motor (copyright 1971) it goes into a little detail about the system but not in deep. its hard (for me) to understand what its telling me to do, i can ask him what he in detail plans to do but i wont understand it. i really wish i knew what i am doing. the wires are old and not true to the colors that the book tells me. i did notice one thing today when i was tinkering with it was there is a little silver thing under the wire bus its cylindrical in shape with two screw in flanges that ground, it has three wires coming out of the back side (against the power-head) two yellows and a dark brownish black wire, they all three go in to a hardened plastic that looks like it was pored in-to it. one of the wires coming out is corroded and the copper is green. it looks like it may have come in contact with the silver case that its in and has burnt it/melted it. there is a black sappy looking stuff that looks to have come out of it. i don't know what its for or if it may be a problem, any help?

Re: 1972 evinrude 125hp converted?

Jm, the thing you are describing is a rectifier the 2 yellow wires should come from the stator. Just thought I would say hi and post something i could help with. I am having similiar issues with the amplifier on my 68 selectricshift -- Edit: Sorry I got so excited that I could help someone i didn't read the last part the rectifier converts ac current to dc current to be used to charge the battery.

Re: 1972 evinrude 125hp converted?

A toasted rectifier could be the result of someone hooking a battery up backwards. I don't know enough about the pulsepacks to offer an opinion of what effect such a situation might have played in your overall problem.

The mismatch in wire colors also suggests that someone did some rewiring on the motor. I would say that its time for you to find a friend who can help you trace the wiring from the diagram in your manual, to make sure the work was done correctly. The use of other than standard wiring color is not a huge issue, as long as you understand what is going where and the job was done correctly. Be sure that the correct wire gauges were used too.



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Re: 1972 evinrude 125hp converted?

well was messing with it some more, for some reason i don't know what i did but at one short time i did have spark on the number one spark plug. then it went away, idk if this matters but i thought i would tell you

Re: 1972 evinrude 125hp converted?

If I may say one more thing before I bow out on the different systems. The 1972 125hp with the Prestolite pulse pack gets it's power from the boat battery. That is unlike the newer motors where the power pack gets its power from the stator. The 1972 will run if you were to completely disable the alternator stator---until the battery goes so dead it no longer is able to power the ignition.

Having said all that, it is possible that is exactly what is happening. Since the rectifier is obviously burnt up, the alternator is not recharging the battery and it might be getting too low. Mind you, that is guesswork.

Johnny, let me tell you something man-to-man. My wife hates (refuses) to take the car in for work. She doesn't understand what they are telling her. Which is OK. But I tell her that it is much harder to flim-flam a woman than a man because the woman will stand up and demand to know WHY and HOW it needs this or that. A man won't admit his ignorance and will fall for anything. I saw that time and again when I was doing motor service for a living. I never flim-flamed anybody. But if I told a man his motor needed this or that, he would say sure, go ahead. But Lord Help if he had his wife bring the boat in. It is OK for a woman to be ignorant and ask questions. ER, I mean ignorant about motors, that is....Oh, you know what I mean. What I am saying is stand up and demand answers or take it someplace else. If there is noplace else, perhaps you are right--you may need a better/newer motor that the techs know how to fix.

Re: 1972 evinrude 125hp converted?

Good point about the alternator and battery - a fine point that I missed. I guess that would be true of the points, distributor/rotor and amplifier system, as well. If the rectifier is not converting the AC voltage that comes from the alternator into DC voltage for the charge system, the battery won't be charged and there will be no voltage for the ignition system.

Let me also say something about the knowledge issue. I have been fooling with old OMC motos for a long time, but I tend to learn them as I acquire a another one and have to fix it. I also learn a lot in here. Both of these things said, I have made a few mistakes in my posts about your system. I try not to make such goofs, because they mislead a person who is trying to fix his/her motor, but it happens. I guess my point is that there is no shame in not knowing something.

I'll also say that if you hang around here long enough, you'll learn a great deal about your motor and a few others, so welcome to the sometimes frustrating, but often very rewarding world of outboard motor repair.



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Re: 1972 evinrude 125hp converted?

Jay, I would say that you are one of the more knowledgeable people that hang out here.