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Chasing spark issue johnson 140hp 2 stroke

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Johno140

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Hi guys this one is a hard one....so motor has been running rough running up then down up then down then stalling. Check fuel side of things 1st all ok, Did the tests on the coils appear ok and have continuity on all leads. But when i tested each coil output with the 716 jump test i got great spark on coil 1 and 4 but 2 and 3 wouldnt jump. So i replaced the power pack with a spare i had from another 140 motor engine i bought for spares. now it runs with out ideling up and down but still cant get the strong 716 spark jump on coils 2 and 3 even though they test ok with multimeter and are within range 275 plus minus 50. All coils sit at around 250 mark. Im wondering if the engine is running only on cylinders 1 and 4. Starts and stops ok and engages prop in forward and reverse and engine runs. Im not sure why i cant get coils 2 and 3 to show strong spark and do the 7/16 spark jump. Im working through the manual re testing components but as the power pack is sealed unit (not like the manual shows) it is hard to test input and output wires to see if some of the input/outputs are working correctly ie from stator etc. Any help appreciated.
 
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what's the model #? we need to know if it's a crossflow or looper motor. powerpacks aren't directly tested, only isolated. Test the stator cranking output first. if you see 100+ volts should be ok. next test (depending on model) timer base or sensor coil output. 4v is plenty. if its a looper, pop off the flywheel and check the magnets. if you don't have it, buy the FACTORY service manual and a $20 ebay special DVA/peak reading adapter for your digital multimeter. the manual will work you through the steps to test. it's actually fun.
 
Johno140 said:
Hi guys this one is a hard one....so motor has been running rough running up then down up then down then stalling. Check fuel side of things 1st all ok, Did the tests on the coils appear ok and have continuity on all leads. But when i tested each coil output with the 716 jump test i got great spark on coil 1 and 4 but 2 and 3 wouldnt jump. So i replaced the power pack with a spare i had from another 140 motor engine i bought for spares. now it runs with out ideling up and down but still cant get the strong 716 spark jump on coils 2 and 3 even though they test ok with multimeter and are within range 275 plus minus 50. All coils sit at around 250 mark. Im wondering if the engine is running only on cylinders 1 and 4. Starts and stops ok and engages prop in forward and reverse and engine runs. Im not sure why i cant get coils 2 and 3 to show strong spark and do the 7/16 spark jump. Im working through the manual re testing components but as the power pack is sealed unit (not like the manual shows) it is hard to test input and output wires to see if some of the input/outputs are working correctly ie from stator etc. Any help appreciated.
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AJ140TLCUA MODEL.NUMBER
Sorry guys AJ140
 
Ok cleaned all earth points, replace a dodgie coil pack and power pack from spare.looper motor i had amd works fine. Firing on all cylinders sounds angry as! Starts1st tune of key!����
 
I think that was definately adding to the issue. But replaced a fault coil pack as well as the main power pack. So the order was power pack, then found fault coil not putting out spark then could get strong spark on cyl 2 amd 4. Both ⁸leads would not jump 716 gap test. Pulled off all coils lightly sandpapered engine block ad both side of metal earth strip on each coil amd bang fixed! Id say the were 3 issues, earth a coil pack and the main power pack as well.
 
Me either. As far as pics. But good deal , she's running again. Great news .
I'd like to see u put coil pack back , back on just for curiosity to see if. Coil pack or cdi box was issue ? Or Ground.
 
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