electrical thoughts…

[amuller]

Been going through the wiring of the 1970 3 cylinder 60 hp. Of course, it’s similar but not identical to the ’72 V4.

The wire seems to be a mixture of rubber and PVC insulation. A couple of the rubber-insulated lines are dried out and crumbled. This was also true of the points lead on the V4. At first I thought they were burned up from overload, but now it seems to me that the problem is just poorly compounded rubber insulation material leading to short life (not that 47 years is all that short). Anybody have any thoughts on this?

The leads on the rectifier are in bad shape. There is a lot of info or opinion on line about problems with the unregulated flywheel alternators, voltage excursions, damage to CDI boxes, etc. CDI makes a regulated retrofit version (193-3408) costing $60-100 or so. (Best price I found here: http://www.blackbearsportinggoods.com/J … m?click=12)

There is a rather generic regulator/rectifier used on many 4-wheelers, scooters, etc. A common number is SMDT250C-4 (not sure what the suffix means) and they can be gotten for around $15 and up. https://www.amazon.com/GOOFIT-Voltage-R … B015WC0EN8

Specs here from an Argentine maker: http://www.dze.com.ar/en/producto/2431/ … 20350%204T.

Note, though, that these are for 3 phase input and the old OMC alternators are single phase.

There are single phase units even cheaper and supposedly rated at 25A: http://www.ebay.com/itm/like/371889077451 (But do these need a heat sink?)

Last question: CDI advises to remove the clipper box? What do others think?

[fleetwin]

Well, I don’t know how to advise about the wiring, I’m not sure I understand the condition you are describing. Again, the best solution to damaged wiring is a new/used control box with decent wiring. I think CDI makes replacement engine wiring harness’ for this engine as well. The lead from the points to the amplifier box is critical, so I would look for a replacement timer base or perhaps someone just happens to have a new OEM lead assembly.
As for the recitifier, I would just use the standard OEM rectifier replacement. The engine provides a pretty constant draw on the battery, so no regulator is necessary, there is little chance of over-charging the battery….
The clipper circuit is there to reduce the impact of high voltage spikes the amplifier. The biggest causes would be things like loose battery connections or poor wiring, or perhaps and internal battery problem. So, in effect, this clipper circuit is a fairly basic voltage regulator in itself…
I surely would not remove the clipper from an older/original amplifier box. The question is whether or not newer replacement amplifiers have some sort of internal voltage spike/regulator built in making the external clipper circuit box redundant. I have wondered about this for some years now. I would be interested in hearing why CDI recommends removing the clipper, and if so, is this just for newer replacement amplifiers they sell.
Granted, the testing procedures for the clipper boxes are vague, the test results are sometimes confusing as well. I guess the best way to protect the amplifier is to install a voltmeter (not an ammeter) in the dash that is relatively easy to wire by tapping off the key switch inside the control box.

[vintin]

Seems a regulated output should also regulate out any spikes. The clipper circuit box likely absorbs some power output from the stator and with some of these system the output in only 6 amps max, which isn’t much. I like the idea of voltage regulation and with modern electronics it should be easy enough to do.

As the load is reduced on a stator the voltage should rise. I talked with a rep at CDI and he said to reduce output of a stator switches can be put in leads that lead to the rectifier. I asked if this could result in a high enough voltage to ‘punch through’ the insulation on the stator and he said it was not near high enough of a voltage to be concerned. This leads me to believe that a good regulator could reduce the load on the stator once the system was pretty much charged up and would reduce stator temperatures.

[amuller]

I wrote a response and it disappeared. Second time in two days. I’m getting frustrated.

[amuller]

OK thanks for the responses. I’ll try again.

The deteriorated wiring insulation wasn’t buried in any harnesses, but where it could be readily-enough replaced. OMC seems to have used a combination of rubber and PVC insulation, and rubber insulation is known to be short-lived in many cases. Think of an old tool cord or extension cord. The points lead sees to be an extra-flexible wire resembling a miniature welding cable–multiple stranded strands. Perhaps it is "test prod wire." Again, crumbled rubber insulation on the V4. Is there something non-obviously critical about this lead? The good news is that all the electrical items seem to check out–though I am not entirely confident of the clipper box tests as called out in the manual, so with the wiring sorted the motor should run.

As for regulators, the usual sort is shunt regulation that keeps full output going and dumps the excess. Series regulation is less common and does allow the stator voltage to rise. There are pros and cons but neither is ideal. I tend to agree that a big battery fed by a 9 amp unregulated alternator should not be a problem, BUT there are a lot of reports of such problems. It’s interesting that my OMC manual also shows a more sophisticated flywheel alternator design using, in effect, a field coil for regulation.

[fleetwin]

Like you say, this engine puts a pretty good constant load on the battery, especially when shifted into neutral or reverse. It is usually just loose battery/cable connections that create voltage spikes that might harm the amplifier. I have never heard of any overcharging problems with this system on the battery CD engines, or experienced a damaged stator winding. Later model mag CD engines that put no load on the battery were subject to overcharging problems.
I would be interested in seeing the manual describing the more sophisticated system, and read the reports of overcharging on battery CD equipped engines.
The alternator system is really simple on this engine, the only confusing part are the shift diodes plumbed into the alternator to keep the engine in neutral while the flywheel is spinning with the key turned off…

[fleetwin]

quote fleetwin:

Like you say, this engine puts a pretty good constant load on the battery, especially when shifted into neutral or reverse. It is usually just loose battery/cable connections that create voltage spikes that might harm the amplifier. I have never heard of any overcharging problems with this system on the battery CD engines, or experienced a damaged stator winding. Later model mag CD engines that put no load on the battery were subject to overcharging problems.
I would be interested in seeing the manual describing the more sophisticated system, and read the reports of overcharging on battery CD equipped engines.
The alternator system is really simple on this engine, the only confusing part are the shift diodes plumbed into the alternator to keep the engine in neutral while the flywheel is spinning with the key turned off. The clipper circuit is a bit confusing to test, but is really just a crude voltage regulator.

[amuller]

The alternator system is at page 6-23 of my manual, which is a scan described as "Johnson Evinrude 50-125 hp service manual 1958-1972." I got a screenshot of the page but don’t know how to upload it here. I can email it to you of you send me an address.

It is interesting. Have never seen or heard of a field-controlled flywheel alternator.

I agree it is simple once figured out. The confusing diagrams in various formats, and faded-out wire color coding, don’t make it as easy as it could be. But if it was too easy it would be no challenge….

This limited generating capacity might be one of the main limitations of these old motors for modern use.

[RICHARD A. WHITE]

After you enter your text, look below in a box that says "Full Editor & Preview" Click that box and look for a tab that says " Attachments"

Follow the instructions…it will ask you to "Add file" , from your PC,

Then it will show the file you chose, now here is where it gets a little funny, look at where your cursor is in relation to your text…

I hit the "enter button 3 times, then click on the "Place Inline " tab

Then it will add some text in parenthesis that should say something like " attachment"

You can then hit the Submit button after you are done with your text

http://www.richardsoutboardtools.com
classicomctools@gmail.com

[fleetwin]

dkellogg56@gmail.com

Don Kellogg

OK, I’m thinking your manual is not an OEM book, and it describes many different engines/charging systems….The V4 generator alternator systems used up to 1968 were definitely more complicated that what you have on the 72 60hp, I’m guessing your manual is referring to one of these systems….

[Author]

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