1988 Johnson 28hp only starting for a bit when wires are switched

Viperwhy

Cadet
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Aug 18, 2022
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the motor will start for a bit when I put the bottom spark plug wire to the top cylinder and top to bottom. When it’s not switched it sputs and pops but doesn’t go what could it be
 

racerone

Supreme Mariner
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Dec 28, 2013
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My wild guess is that wires from CDI / powerpack to the coils were switched by a club fisted individual.-----Orange / blue stripe should be on the top.----What else do you know about this motor ?----How did it run for you last season ?----Post the compression test numbers here.
 

oldboat1

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Apr 3, 2002
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9,612

On this carb, the needle up on top (idle screw) may need adjustment. Turn clockwise until lightly seated, then open c.clockwise 1 1/2 turns. See if the engine starts and runs. After warmed up, if it runs, turn it clockwise until it backfires or stalls, the c.clockwise 1/4 turn. Let it run a bit if success. Make sure the cooling water is about half way up the shaft.
 

oldboat1

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Apr 3, 2002
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9,612
Maybe check for a sheared flywheel key as well.
Need to take off the FLYWHEEL for that with the correct puller, and check the key in the crankshaft. The key is a half-moon shaped piece -- could be sheared or missing. If the flywheel key shaft is not correctly lined up with the crankshaft key/keyshaft, timing is affected.
 

Viperwhy

Cadet
Joined
Aug 18, 2022
Messages
7
My wild guess is that wires from CDI / powerpack to the coils were switched by a club fisted individual.-----Orange / blue stripe should be on the top.----What else do you know about this motor ?----How did it run for you last season ?----Post the compression test numbers here.
Well that is what was causing it the motor came with the hull and trailer, it’s starts but idles like **** you gotta move the neutral throttle to keep it going, but now there’s a visible purple spark on top of the top coil😅 could that be causing it?
 

Viperwhy

Cadet
Joined
Aug 18, 2022
Messages
7
Need to take off the FLYWHEEL for that with the correct puller, and check the key in the crankshaft. The key is a half-moon shaped piece -- could be sheared or missing. If the flywheel key shaft is not correctly lined up with the crankshaft key/keyshaft, timing is affected.

Getting the flywheel off took us a few weeks wouldn't move without heat, key looks fine and all wires and stuff look good aswell
 

racerone

Supreme Mariner
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Dec 28, 2013
Messages
37,818
Should never need heat to take a flywheel off a 25 / 28 / 30 HP model.----I do not see answers to questions.----Good luck sorting this motor out.
 
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