US Member - 1 Year
Topics: 47May 31, 2017 at 11:31 pm #58713
Much better system than the 1963 OMC Dual Deluxe. Hey you have forward no matter what!May 31, 2017 at 11:40 pm #58715
I agree, the forward gear fail safe always seemed like a good safety feature to me also. OMC claimed the coast guard didn’t like the system, maybe if was actually the OMC bean counters who didn’t like it…June 1, 2017 at 12:44 pm #58766
Fleet, I think this is a very simple, unregulated, single-phase alternator. So it probably does have only two diodes, one on each end of the coil. The good news is that it would be easy to make a functional substitute.
The points are probably just in need of cleaning. The gap looks like about ten thou to me but haven’t gotten into them yet. The distributor rotor and stator look OK to me, no sign of any carbon tracks or cracks. So I’m expecting to have spark at the plugs when I put it together. Wow, those point sets are expensive: close to $75 new and $25-30 on ebay.
I admire the system used by West Bend on the 80 hp four: four sets of points, spaced at 90 deg, each firing it’s own coil. What could be simpler, relatively speaking?
As for the default-to-forward control logic, I can see pros and cons to it.June 1, 2017 at 7:48 pm #58786
OK! Finished taking the ignition apart. Points a bit crudded up. I’ll take them apart and polish the points. (Why are these point sets so expensive?) All else seems fine, except for being a little greasy. I notice: Not a single burr turned up on a single screw head. Either this has never been apart or it was worked on by a well trained mechanic who used ground-to-size screwdrivers and otherwise knew what he was doing. So I’m challenged to do an equally good job now.June 2, 2017 at 2:36 pm #58816quote amuller:
Yes, simple unregulated charging system….But, I think there are four diodes…Here are the simple resistance checks….
Ohm meter on high scale with rectifier leads isolated from all others and ground:
Connect one ohm meter lead to the rectifier case/ground
Now connect the other ohm meter lead to each of the two yellow leads, one at a time. You will either see an infinite reading, or some high reading less than infinity, you should see the same open or less than infinite reading on both tests.
Now, swap the ohm meter leads so the other ohm meter lead is connected to the rectifier/ground. Again, you will see either an infinite reading, or some high reading less than infinity. You should see the opposite readings than noted in the first test.
Next, you will connect one of the ohm meter leads to the red rectifier lead. Connect the other ohm meter lead to each of the rectifier yellow leads one at a time. You will see either the infinite or high reading on both leads.
Finally, swap the ohm meter leads and repeat the above test. You should see the opposite readings you saw in the previous test….
Any shorted or open diodes mean the rectifier is shot….New/used but good ones are easy to find and affordable, no need to make one up….
There are also two "shift diodes" in this system, this unit is affectionately known as the "monkey balls". I’m pretty sure there are only two diodes in this critter. This thing is here to supply current from the alternator to the shift solenoids after the key is turned off but the flywheel is still spinning. Otherwise, the engine would slam into forward gear when the key is turned off…
The resistance tests are pretty similar to the rectifier tests, just less diodes to check.
Ohm meter on high scale, shift diode leads isolated from all others and ground:
Connect one ohm meter lead to the diode purple lead, then connect the other meter lead to each of its yellow leads, one at a time….Note the readings, either infinity or a high reading, both should be the same.
Now, swap the ohm meter leads and repeat the above test. You should see the opposite readings noted in the above test.
Any shorted or open diodes mean this thing needs to be replaced. A messed up shift diode could certainly affect alternator output as well.June 2, 2017 at 4:01 pm #58821
So you’re saying test as a bridge rectifier circuit? Makes sense. I’ll have another go at it. For me, an electrical schematic would be very helpful, as opposed to the various pictorial representations. Are any such available?
Interestingly, the insulation is crumbled on the black lead from the points to the disconnect. I’d guess improperly compounded neoprene.
On a couple of other matters:
Should I expect to find the usual hard-anodized aluminum pump body in this motor? I can order just the impeller, but there are "chrome pump kits" around at reasonable prices. Not sure if these are the bronze pump body or the plastic-with-metal-liner type. Worthwhile?
I haven’t touched the fuel pump or carbs. There are obvious hard hoses to change out. anything in particular to expect here?
amJune 2, 2017 at 4:14 pm #58823
Since you called it a bridge rectifier, I assume you know what that is and how to test it. And yes it is a bridge rectifier.
Water pump: If it still has the original pump, it is the old aluminum housing. And I strongly advise replacing it with a complete new pump kit with plastic housing/stainless liner. We had a lot of problems (fried motors) with the aluminum one. Of course if it already has the plastic pump, all you need is a new impeller.June 2, 2017 at 5:39 pm #58828
The monkeyballs tested out OK.
The rectifier did not. Positive side diodes were open. I should have caught this first time around.
There are a lot of different part numbers, some claiming to include a regulating function. Does it matter? I have a stash of generic bridges I could mount on a piece of aluminum and add leads to.June 2, 2017 at 5:58 pm #58829
The original non-regulated ones worked out for thousands of owners. OK, some owners discovered the voltage could go to 16V or more. But if you don’t know, it won’t hurt you. (just sayin). And sure, a generic one can work too, if it is rated for high enough current and voltage, and properly heat sunk. OK, some electronics balk at the 16V. I have my own opinion of boat accessories that won’t work on boats. Shame on them.June 2, 2017 at 6:37 pm #58832
I ordered a 583408 regulator/rectifier for $19.00.
Frank: What was the problem with the aluminum pump body?June 2, 2017 at 8:24 pm #58834
OK, the 583408 is the correct rectifier, so that will work out.
You mentioned something that might be important to figure out before reassembling distributor/flywheel. You mentioned that the lead from the points has peeling insulation. It might just be that this lead is broken, or shorted to the ignition plate for just this reason. In either case, you will have no spark, so examine this lead(s) carefully by eye and with an ohm meter before reassembling.
It is not often that I don’t recommend doing a water pump job, but this engine is just that exception, for now anyway….
Getting that gearcase down without damaging the shift solenoid leads can be real tricky, reassembling can be just as tricky. This engine has TWO water tubes that have to be lined up as well. So please, let’s get this thing running properly first, then we will attack the gearcase/water pump. There is nothing really "wrong" with the original aluminum pump body, especially if it was used only in fresh water. But, there is always wear to the aluminum which affects pump performance. Many of the bolts will probably have to be "heat treated" as well in order to remove them on a salt water engine. The aluminum body will definitely be pitted/worn/corroded if the engine was used in salt water. So, if and when the time comes to do the pump job, do spend the bucks for the complete replacement kit which includes the SS liners that slip inside a plastic body.June 2, 2017 at 8:27 pm #58835
I believe that is a rectifier, not a rectifier/regulator. But it should be fine and that was a good price.
My water pump saga goes like this: Back along that period of time, we started getting burned up motors, one right after the other. I’m talking about nearly new motors here, generally less than two years old. The impeller hub would separate from the rubber and looked like they had never been bonded at all. This usually happened at high speed, and the instant pump failure would cook and seize the powerhead before the driver even noticed anything. So quickly, if fact, that the warning horn didn’t even have time to heat up and sound off. Then the boat sits there dead in the water and smoke coming out as the paint and wires burned off. I will say this: It was a good test for Evinrude 50:1 oil. If the guy happened to be using that,
the pistons often survived. Any other oil and it was goodby pistons and re-bore time. We had so many failures that I kept a complete stock of pistons on hand.
OK, now you probably are asking "Why?". So did we. We were in contact with Evinrude several times, and they also asked "Why?" Nobody had an answer. One factor, not to be ignored, was these were salt water motors. But they were supposed to run in salt water weren’t they?
This went on for way too long, and finally Evinrude told us they thought it was caused by electrolysis. I’m thinking "yeah, right". But an examination of impellers removed before they separated completely showed that they started to separate at both ends of the hub and progressed inward. So electrolysis might have been the culprit, attacking where the rubber meets the road, so to speak.
Anyhoo, soon after that, they got rid of the aluminum housings and went to plastic/stainless. And lo and behold, the impellers seemed to hold up better. Unfortunately, I don’t have the final answer because I left the outboard shop in 1978. And surprisingly, today nobody else seems to even be aware of the problem. Maybe it was dissimilar metals in salt water = electrolysis. (????)
But I replaced those aluminum pump housings whenever I got ahold of one.
Your mileage may differ.June 2, 2017 at 10:08 pm #58842
Frank makes a good point about the electrolysis. I remember this on the early 9.9/15s with the aluminum housings. These aluminum housing did have SS liners, but that salt water is powerful stuff. The salt would work its way between the SS line and the aluminum hsg and crush the liner inward, this eventually led to excessive drag on the impellers and spun hubs….
And yes, that part mentioned is only a rectifier, just as it is supposed to be on this engine, no regulator. I guess the "clipper circuit" is the regulator because it grounds/shorts the yellow alternator leads is voltage spikes are sensed…Don’t know what voltage reading this crazy thing kicks in at though…The battery CD ignition and gearcase electronics present a pretty constant load that should keep the battery from being over charged…I think, like Frank mentioned, that the clipper circuit was meant more to prevent large voltage spikes from loose/corroded cables, a bad battery, or perhaps the nimrod who pulls the battery cable off while the engine is running…June 3, 2017 at 2:43 pm #58880
I used to live on the East Coast. Motors I could pick up at scrapyards for $5…. But I didn’t enjoy working on salt water motors where nearly every fastener was a challenge. Minnesota motors are rarely very corroded by comparison, given fresh water and a relatively short boating season.
I doubt the bad wire insulation is actually causing a problem, as it sits in an vinyl sieeve and the wire it shares the sleeve with seems OK. But I’ll pull it out and replace it.
If this motor turns out to be a runner–feels like it will, but one never knows–I expect to want to sell it and get a Bearcat. So I want to go through it well enough to ask a few bucks for it in good conscience.
Question: I know that OMC has made magnetic drain plugs at some point, as has Mercury. Given the sensitivity of these gearboxes to debris in the lube, would it make sense to use them? 318544, Sierra 18-2375, GLM 21731?
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