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2004 Johnson 175 No Start

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czbill

New member
2004 Johnson 175 No Start, model J175PXSOE. Went into limp home mode, then the next day no start.

I went through the testing procedure in the manual and determined the power pack was bad due to low voltage to the primary of the coils. Voltage in the 40s on the port side and in the 60s on the starboard side, supposed to be about 100 volts. Purchased new power pack and it started and ran. Next day no start, tested and coil voltages low, same range. Returned the power pack and got a new one. This time I tested before trying to start, same low voltages to the primary of the coils.

Optical sensor seems to be working properly, it pulses the test light as the engine is rotated. Kind of stuck, the boat is on my lift behind the house, would be about an hour tow to get to the trailer to get to the Johnson spe******t. Maybe the regulator/rectifier? I can't find a test procedure for that.

Anyone have experience like this?
 
I retired in 1991 so your engine's design is somewhat foreign to me, especially the optical sensor unit, however...........

The fact that the new pack went south overnight indicates a possible DC voltage being fed to the power-pack. Find the "M" lead of the ignition switch that the black/yellow wire (kill circuit) is attached to and remove that wire.

Ignition switch set to OFF. Attach a volt meter (set so that it will register even a microvolt) red lead to that now empty "M" terminal with the meter's black lead connected to a known powerhead ground. There should be NO reading.

Now, while observing the meter, turn the key to the ON position (Engine NOT running). There should still NOT be any reading. If there is even a microvolt of a reading, there is a intermittent short within the ignition switch, in which case, replace it....... See the following pertaining to those two "M" terminals.

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Voltage To Powerpack Failures
(Magneto Capacitance Discharge Systems)
(J. Reeves)

The usual cause of having those type powerpacks fail repeatedly is having a very small of voltage applied to the Black/Yellow wire (Kill Circuit) at the pack. Test as follows.
Disconnect the Black/Yellow wire at the powerpack.

Insert either a ampere meter or a volt meter set to its lowest DC voltage reading between that Black Yellow wire on the wiring harness side, NOT the powerpack side and ground.

With the ignition key in the OFF position, observe the meter reading. Now turn the ignition key to the ON position and again observe the meter reading.

Any reading, movement of the meter needle, even a microvolt, would indicate that battery voltage is being applied to that Black/Yellow wire. If a reading is present, remove the other end of that Black/Yellow from the raised terminal of the ignition switch.

If the reading ceases to exist when the Black/Yellow wire is removed from the ignition switch, replace the switch. If the reading continues to exist, there would be a short of some kind in either the engine or instrument wiring harness.... to determine which, simply unplug the large RED electrical plug at the engine which would eliminate the instrument cable.

Note that the black/yellow wire must not have any other wire attached to it for the following reason!

Keep in mind that any accessory that has 12 volts running to it, especially when turned on, will have voltage flowing thru it and trailering out thru its black ground wire to complete the circuit. If that accessory has it's black ground wire attached to the "M" terminal that the black/yellow wire is attached to.... you will have voltage flowing directly to the powerpack.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
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Thanks for the reply. I'm heading out of town for a couple of weeks today, will make that check when I return and post my findings. I hope I haven't ruined the newest power pack already.
 
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