2.3L OMC No Spark

1990_OMC

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May 17, 2020
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3
1990 170Freedom Fourwinns 2.3L OMC stern drive

My boat has always been reliable. Its developed a new behavior coming out of storage. It cranks, but delivers no spark.

I’ve bypasses the safety switch on the dash
Replaced the coil - which tests within acceptable thresholds on the bench. New points (verified they open and close properly upon rotation), Cap, rotor button, condenser, wires and plugs - verification of no spark condition performed with a Lisle inline spark tester.

Testing completed; Meter hooked to + of coil and - of battery I get proper voltage in both run and start position. This should confirm that the purple/red are getting 12v in Run and the Purple/Black energizes in Start (these wires are bundled in one ring terminal connection - I cannot test them independently at the coil w/o cutting them). Ignition turned to the start pos. the motor cranks as it should bit produces no spark. The single grey wire from the coil to the distributor ohm tests fine. There are two other grey wires in a ring terminal - they do not ohm out at all - they appear to connect to something in the schematic (not identified, but look to have a purple from the alt hooked to the A side of the schematic / grey from the Coil to the B side) that then hooks in the E.S.A module (perhaps my problem is in this area)

When I pull the fuse on the dash, or have the transmission in gear, the engine will not engage the starter - this should confirm the neutral safety switch is operable and my fuses making proper contact.

Any additional thoughts on what I should test or bypass would be appreciated.
 

bruceb58

Supreme Mariner
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Mar 5, 2006
Messages
30,454
One of the two wires on the negative side of the coil is the tach and the other is the ESA. I would remove both of those just as a test. Tachs have been known to fail and short out the distributor.

Do you have a dwell meter? If so, attach the dwell meter and crank the engine and see what kind of dwell you have. If you don't have a dwell meter, buy one. You really need one to set points accurately.
 

1990_OMC

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May 17, 2020
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3
Thanks for the feedback. I do have a dwell, but need to get spark first.

I unhooked the grey wires on the negative side of the coil and it did not change the behavior.

Went back through the distributor today, swapping the condenser just to eliminate that as well.

With 12v at the coil in Ign & Run Key locations, resistance free negative wire from the coil to the condenser / points connection, one would think spark would happen!
 

1990_OMC

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May 17, 2020
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Closing out this thread. Our fault mechanism was nailed down to defective points that were new out of the package. We installed two different sets purchased from a marine wholesaler that did not work. We had to file them down to less than 50% remaining material before continuity was established in a bench test. For fun, we reinstalled them and spark was produced.

Recommendation for anyone reading this that may be experiencing a no spark situation - spend the money and buy Mallory points - they are $27 and are far superior in construction and quality.

With Mallory points installed, my boat once again runs like a top!

Thanks
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
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47,307
you have to file any points as part of the normal service. the contacts will oxidize from sitting.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,454
Just so you know, if you had a dwell meter and just cranked the engine while measuring dwell, you would have realized you had faulty points.
 
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