1985 125HP Force idles on 1&2 cylinders

DKM

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Nov 15, 2012
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1985 125 HP Force, model # 1258X5A. Compression 140-145 on all 4 cylinders. It has new Champion UL18V spark plugs. Starts and idles on top 2 cylinders, 3&4 have no effect when grounded out. It has spark and gas to all 4 cylinders. I have switched coils and C-D boxes in every configuration I could think of. It still starts and idles on the top 2 cylinders. It will clear itself at WOT but it'll miss occasionally. The exhaust is blue with un-ignited fuel from the bottom 2 cylinders. I have read that others have had this problem and read their solutions, none of worked with this beast. Please help. Thanks
 

pnwboat

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Oct 8, 2007
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4,251
Re: 1985 125HP Force idles on 1&2 cylinders

Check the resistance of the stator windings. You should have two pairs of solid Blue and solid Yellow wires from the stator that supply ignition voltage to the CD Modules. One pair of Blue and Yellow wires supplies voltage to the 1st CD Module and the other pair supplies it to the 2nd CD Module. Disconnect each pair. The resistance should read 680 - 850 OHMs. Both pairs should read pretty much the same.

Also make sure the strip magnet on the inner circumference of the flywheel hasn't come unglued.
 

DKM

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Nov 15, 2012
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Re: 1985 125HP Force idles on 1&2 cylinders

Checked the resistance on the strator windings, both sides read 178 on the meter, a tad lower than expected but I thought within range, a the magnets under the fly wheel are tight. I ran the motor in a tank at 3000 rpm and sguirted sea foam into the lower carb, as suggested in a previous thread. It smoked like crazy and left an oily sooty residue, it seemed like #3 started to fire. I've had the fuel and recirculation lines off to check for blockage, they seem to be clear.
Could there be so much of a carbon build up on top of the pistons to prevent firing?
 

pnwboat

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Re: 1985 125HP Force idles on 1&2 cylinders

178 is not a good reading. It's way off. Did you disconnect the wires when taking the resistance measurements?
 

DKM

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Nov 15, 2012
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Re: 1985 125HP Force idles on 1&2 cylinders

Yes we disconnected the plugs from the strator to the CD moduals and tested on the and tested on the blue and yellow leads going into the strator. I'm going to order a new strator.

Thank you for your help
 

Jiggz

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Oct 23, 2009
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3,817
Re: 1985 125HP Force idles on 1&2 cylinders

I suggest you follow PNW's lead first before spending some $$$. Remember just disconnect the yellow and blue wires first and make sure you marked them accordingly. You can even switched these two sets of wires (between upper and lower cylinder sets) to see if the misfiring switches over to the upper cylinders. If resistance reading is withing range, check make sure none of the sets of wires is grounded.
 
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