My 1972 65 hp died while running.

jswilley1 · Dec 8, 2011

I was fishing in the river, and running along, shut the engine off, fished, then run again, shut off, fish, you know the routine. The last time I cranked it up, it ran for a second, then shut off. I have checked the compression,(avg.140 psi on all 3 cylinders) I have plenty of fuel, but no spark. Please give me some place to start looking for an answer.

Joe Reeves · Dec 8, 2011

Re: My 1972 65 hp died while running.

Remove spark plugs. Check the spark. Rig a spark tester so that you can observe the spark jumping a 1/4" gap with a strong blue lightning like flame... a real snap. Do you have any spark at all, and if so, how does it look?

jswilley1 · Dec 9, 2011

Re: My 1972 65 hp died while running.

I did a spark test and I didn't have any spark at all. With this engine being 35+ years old The wiring has discolored some. Do you happen to know which terminal this "purple" wire should be hooked to?

Joe Reeves · Dec 9, 2011

Re: My 1972 65 hp died while running.

Not right off hand but there's only a few wires leading fom the pulsepack, it should be fairly easy to figure out. If not, with the volt meter black lead grounded to the powerhead, you can check out all of the pulsepack wires for voltage safely.

jswilley1 · Dec 9, 2011

Re: My 1972 65 hp died while running.

just to clarify, when you say pulsepack, do you mean the stator? The only purple wires I found were from the automatic choke, and the stator under the flywheel. I checked the voltage on all of the purple wires I could find(there were a few different ones on a junction block on the side of the engine.), and I only got 12 volts leading to the automaic choke. Any Ideas? Thanks for taking the time to help me with this problem.

tx1961whaler · Dec 10, 2011

Re: My 1972 65 hp died while running.

Here are some troubleshooting instructions for your ignition:
http://www.boatpartstore.com/page29.asp

Joe Reeves · Dec 10, 2011

Re: My 1972 65 hp died while running.

Whoa! It just dawned upon me that your model has Magneto Capacitance Disharge Ignition, NOT Battery Capacitance Discharge Ignition.... please disregard my above comments pertaining to voltage as battery voltage being applied to that powerpack would destroy it... and as you surmised, there are no purple wires leading to it. My apologies for the goof.

On that model, you can check the resistance of the timer base timing sensors with a ohm meter.

With the ohm meter set to low ohms, connect the black lead to the timer base Common Ground wire which is a Black w/white stripe wire. Connect the red meter lead to the sensor leads, one at a time, which are the White w/black stripe wires.

The reading should be (I believe. Don't have my book with me.) 8.5 ohms +/- 1.0 ohm. The wires should be disconnected of course. The main point is that all of the readings should be the same.

As before, if the stator is actually melting down, replace it.

To check the powerpack on that model, you can simply switch one of the timing sensor wires that is firing properly from its location on the powerpack to the location that has been firing the coil that is weak..... If that coil now fires properly, that would indicate that the powerpack is okay and the problem is with the timing sensor.

jswilley1 · Dec 10, 2011

Re: My 1972 65 hp died while running.

I was able to test the timing sensors. I came up with 7.9 ohms, 7.9 ohms, and 8.1 ohms. I continued looking for any signs of wear, I found one of the yellow wires coming from the rectifier, going to the junction block, was dried out with broken insulation and several of the strands of copper were broken. I will order a replacement. Is there anything else I can do or test while I wait for this part to arrive? Is there any way to test my stator?

Joe Reeves · Dec 10, 2011

Re: My 1972 65 hp died while running.

The stator can be tested for voltage output and also for the ohm resistance.

Unfortunately I do not have the book on that and the readings do not come to memory. However, I'm sure that anothe member will jump in here with that information.

jswilley1 · Dec 10, 2011

Re: My 1972 65 hp died while running.

Thanks again for all of your help Joe. This voltage output test, is done with the engine running, correct? Do you have any brand of repair manual you would reccomend over another?

jswilley1 · Dec 10, 2011

Re: My 1972 65 hp died while running.

All of the guides I have come across give me resistance limits and voltage limits. What doe the term, DVA translate to?

jay_merrill · Dec 10, 2011

Re: My 1972 65 hp died while running.

If you are getting no spark to any of the three plugs, the first place to look, is the key switch. There is a yellow/black wire that is attached at the lower left terminal of the powerpack. Remove it and try to start the engine. If it runs on all three cylinders, the switch is shorting out internally.

If the test doesn't work, my guess is that your powerpack has gone south.

Be aware that you will not be able to shut the engine down with the key switch, when the yellow/black wire is disconnected. You will have to actuate the choke.

Joe Reeves · Dec 11, 2011

Re: My 1972 65 hp died while running.

Yes, as Jay states above, if you regain spark by simply removing the black/yellow wire from the ignition switch OR from the powerpack.... that usually indicates a shorted ignition switch. I thought that was mentioned earlier by someone but apparently not.

jswilley1 · Dec 11, 2011

Re: My 1972 65 hp died while running.

I tried removing the yellow/black wire, still nothing. I have been reading other threads and found testing methods for the stator. I'll try those and see what I come up with.

tx1961whaler · Dec 11, 2011

Re: My 1972 65 hp died while running.

A DVA is an adapter for a digital multimeter that lets it read short duration, high voltage pulses. They can be purchased cheaply, and are also not very hard to make if you are so inclined. It's a diode, capacitor and bleeder resistor set up as a basic rectifier circuit.

jay_merrill · Dec 11, 2011

Re: My 1972 65 hp died while running.

At this point, I suspect a bad powerpack. The applicable test to troubleshoot the powerpack, is to use a neon test light on each of the primary ignition leads. They are the leads that go from the #1, #2 and #3 terminals (top three, left side of powerpack, facing it), to the ignition coils.

The manual calls for use of an OMC neon test light, but few people have them anymore. I've never used the type that you can buy at a hardware store, but I would assume that one would work.

The procedure is to attach/touch the "hot" lead of the neon test light to each of the primary ignition terminals, one at a time, while grounding the other lead. You crank the engine as you do this. If you don't get a light, or get an intermittent light, the circuit in the powerpack is bad. If you get a faint light, it is weak. A strong, steady light indicates that the powerpack is OK.

Edit: I forgot tomention that you must disconnect each of the primary ignition leads from their respective terminals, before doing this test. Mark the leads (1,2,3), so you know where to reinstall them.

jswilley1 · Dec 12, 2011

Re: My 1972 65 hp died while running.

I'm not sure if you saw, but I was able to order a new rectifier. I have to wait for that to come in, then install it. Then I can test the powerpack. Is this neon test light anything like the old 12 volt test light used in automotive repair? If not, where can I find the correct test light? I still haven't been able to locate a DVA tester locally. I want to try it to make sure it will fit my tester.

levi_tsk · Dec 12, 2011

Re: My 1972 65 hp died while running.

it might work ... but a dva adapter is a better solution i built my own for about 5 bux you COULD use a multimeter alone but youll get an average or the voltage since the HV from the power pack is for such a short duration theres a formula for "deaveraging" it but its complex and i dont have it handy
but you may not need that as your power pack could be a complete dud stick the (+) multi meter lead to the coil side of each output on the power pack and ground the other(-) lead for the multi meter heres a diagram for a dva adapter and instructions

levi_tsk · Dec 12, 2011

Re: My 1972 65 hp died while running.

if you dont get volts on the output side of the pack back track to the yellow wires coming from the stator if you get a reading there its deffinitely the power pack
its important to note that power packs are heat sensitive and will burn out if the engine overheats

oh and set you multi meter to 200acv or something close to that

jay_merrill · Dec 12, 2011

Re: My 1972 65 hp died while running.

This is what I am talking about.

As I said, I've never used one on an outboard, but they are supposed to work for a wide range of voltages. Both for the purposes of this thread and in general, I'd love to hear from anyone who has successfully used one.

My 1972 65 hp died while running.

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