Mechanic Advice Needed

[HitRanger]

I have a 1972 Johnson 65hp outboard model 65ESL-72S. Motor runs good on 2 cylinders and goes into forward and reverse just fine. The only problem is that the top cylinder will not get a spark from the plug wire. I took the ignition coil off, and found a break/burn in the wire at the 90 degree spark plug boot. I replaced the entire ignition coil assembly, including a new spark plug, boot and wires. I have tested the continuity from the orange wire (un-hooked from power pack) to the end of the plug wire and it is good. Motor runs pretty good on 2 cylinders, but the top cylinder is still not getting spark from plug/coil, and I do not know what to check next. I would appreciate some advice on what to do next. Thanks.

 

[F_R]

Re: Mechanic Advice Needed

Gotta be a bad power pack, or a bad sensor under the flywheel. Or bad wire between the two. Here is where you need a DVA meter to check it out. Otherwise, guess an hope you guessed right.

 

[Joe Reeves]

Re: Mechanic Advice Needed

Remove the spark plugs.

At the powerpack, switch the top coil orange wire with one of the other coil orange wires temporarily. If that top coil now sparks, the problem is usually the powerpack.

However, before purchasing a new pack, remove the 3 white/black wires and the 1 black/white wire from the powerpack (make a note as to what goes where), then compare the ohm readings between the 3 white/black wire(s) and the black/white wire, one at a time. They should be extremely close to being the same. If memory serves me correctly, the ohm reading should be 8.5 ohms +/- 1 ohm.

If any of the 3 wire readings vary, one of the timer base timing sensors would be faulty. If they all read properly, consider the powerpack to be faulty.

Let us know what you find.

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http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1