1987 Mercruiser 165 4 cylinder No Spark

John_B

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Jun 29, 2020
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17
I recently bought a 1987 that I'm told ran last time it was out, but it was 7 years ago. Boat turns over just fine, but no spark. I've followed the guide for troubleshooting points in the adults only section. I have 12 volts on positive side of Coil, Coil was replaced from a GT63 to an E30. Points appear good, condenser not so much. I'm having trouble locating original part #'s and what options I have for replacement with parts available locally. I ordered an Ignition kit from west marine but due to Covid-19 that's going to be awhile getting here. My Son bought this bought thinking I could easily fix it. I really don't want to let him down. I have no spark with old coil which the bolt broke when removing or the new Coil. I did NOT due the tapping negative test to simulate a spark.

Any ideas would be greatly appreciated.

Thank you
 

Bondo

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Points appear good,

Ayuh,...... Welcome Aboard,....... Did ya atleast sand or file the points,..??

Are the points makin' ground,..??
 

John_B

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Jun 29, 2020
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Thank you. Yes Points were sanded. a bit of Sulfur came off doing that. With a meter I have ground at the points, but at no point in the ignition cycle do I ever get ground at the negative terminal of the Coil. I tested the wire from the Points to the coil and zero resistance. As I understand it, without a negative signal at the coil, it will never fire.
 

John_B

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Jun 29, 2020
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So now, I've replaced Coil, Points, Condensor, Cap, Rotor and still no spark. all parts purchased at Mercruiser Dealer/Marina.
 

alldodge

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at no point in the ignition cycle do I ever get ground at the negative terminal of the Coil.

Then your points are not adjusted correctly. When the distributor rotates the point should close on the flats of the distributor lobe. When points close, they ground the negative side
 

John_B

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Jun 29, 2020
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Then your points are not adjusted correctly. When the distributor rotates the point should close on the flats of the distributor lobe. When points close, they ground the negative side

Since then, I've replaced everything and set the gap at 0.022. I'm thinking the problem must be elsewhere and not in the ignition circuit.
 

DanD34

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Aug 3, 2019
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I''m not trying to insult your intelligence but I bring this up because I've seen it happen. You adjusted your points while at their widest open position, correct? I once saw a guy adjust them to the spec with the shaft turned to where the points should be closed. It's not a very complicated system. With a multimeter should be able to figure out where in the circuit the break is.
 

John_B

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Jun 29, 2020
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I''m not trying to insult your intelligence but I bring this up because I've seen it happen. You adjusted your points while at their widest open position, correct? I once saw a guy adjust them to the spec with the shaft turned to where the points should be closed. It's not a very complicated system. With a multimeter should be able to figure out where in the circuit the break is.

lol feel free to insult my intelligence. However, in this case, yes, I set them at the top most position on the Distributor. I really thought I'd at least have a Spark, even if it didn't start. My concern at the moment is that the points I bought didn't have a bolt with nuts for attaching the Condenser and negative from Coil. The dealer told me that they just slide in and are held in place. I'm at a loss as to what is causing the no spark issue. I'm 3 weeks from them being able to look at it too. :(
 

nola mike

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The no spark issue is caused by you not having your coil grounded when the points are closed. Like Dand34 and alldodge said, rotate the dizzy till the points are closed. At this point your coil (-) should be grounded. If not, ground one end of your meter and go from connection to connection until you find your break. I'd start on either end of your points.
 

John_B

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Jun 29, 2020
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Well it ended up being the point gap. However, while it ran at home, when I dropped it in the water, it started, ran for a few minutes and now tries to start but never successfully does. Even back out of the water, same problem. At least I have a spark now. I checked the fuel filter, it's fine. Fuel is getting to the engine.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Well it ended up being the point gap. However, while it ran at home, when I dropped it in the water, it started, ran for a few minutes and now tries to start but never successfully does. Even back out of the water, same problem. At least I have a spark now. I checked the fuel filter, it's fine. Fuel is getting to the engine.

go back to the points. gap them, then verify the dwell with a meter, then set timing
 

John_B

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Jun 29, 2020
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well at this point, I'm just taking it to a dealer for repair. This way they can put it on the water and completely test it. Nothing like testing at the ramp while people are waiting to get in and out of the water with their watercraft.

I did check the gap on points. It still was correct. I suspect the 7 years it was out of water, something else might have failed while sitting in the water. At home, I was pumping 80 PSI of water via the hose into the system. In the lake that same intake is dependent on the water pump to be working correctly. I'm wondering if it failed. Just guessing. That's why it's better to just let the dealer work on it.
 

tank1949

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or that old of boat, distributor may out of round or need to be replaced. been there! I thought MC's were all pointless by 1987? New to me...
 

silverseal99

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Aug 9, 2019
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Years ago I had a Merc 165 with points and 6 volt ignition. I crossed it with automotive and bought an electronic "pointless" conversion kit from Summit Racing. It was a straight swap, took about 10 mins to install, and didn't even change the timing. I tossed the points, removed the load resistors (which cut 12v to 6v to conserve the points), and never had an ignition issue again. Best $75 I ever spent on that boat and it was a great boat.
 

Berniemcc

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Jul 8, 2020
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Condensers are not reliable. Try changing that even if you’ve just replaced it. They do have a shelf life
 

Bondo

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Do you have a link to that electronic ignition?

Ayuh,.... Search Pertronics for the conversion, or Delco Voyager for a complete drop in distributor conversion,.....
 
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