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Timing jumps what likely cause Power Pack?

T

TrickyRicky

Member
1978 55hp Johnson Recently acquired no history of past.
I have a factory manual
New engine wire harness
Link and sync good
Compression 140 both cylinders
Reed good
Check coils with spark tester very good and ohm good
Rebuilt carbs (very clean before rebuild), new plugs, clean and runs OK mostly
Checked engine temp with infrared about 150+ - depend on where check. Did find one "hot" spot at the top of block between cylinder head and stator/flywheel


I can get it to run just fine in a trash can at home 98% time
At the Lake it usually runs fine to start and within 5-10mins goes bad.
There is some intermittent electrical problem that is driving me crazy. Seems like a heat soak issue.
Sometimes it starts to run very poor at idle and all running speeds. Will stall and is very difficult to restart
What I can say is that it started to run bad in the trash can today. I put the timing light on each coil wire and it was lighting.
Check the timing and it was off huge. It seemed to be off so much the numbers weren't even close enough to light up on the mark.Instead of say the 12 oclock from the front pointer (and looking toward front) I would say it was somewhere around 1-2 oclock position if that makes sense. And jumped back and forth a bit
After maybe 30 secs timing went back to normal and started running OK again. I have cleaned and check all the wiring connectors an check all the wires for bad spots and found none. If the problem goes away before you start diagnosing it what should I do?
Would the likely culprit be the power pack?
 
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Pulling flywheel using three hole bolt puller................

Have all bolts evenly threaded in.

Tighten center puller spindle as tight as possible.

Using some kind of pry bar under flywheel, raise flywheel to eliminate the small amount of play that exists.

Belt that center pulley spindle with a good size hammer...... hard!
 
Ok I just broke on of the three bolts off in the flywheel. Got it out luckily. Heading to hardware store to buy some more and try what you said Joe. Thanks will report back
 
Got the flywheel off. Key looks fine. Stator looks like nothing burned. There is one laminate on the stator that is rubbing the magnets. The laminates and magnets have just a light dusting of rust. What should I check next?
 
I unscrewed the stator from the plate and visually checked it. Looks OK to me. If I check th pick up coil and the other components with a meter and find no fault What would likely cause a timing issue like I have?
 
Ok I checked the sensor coil and charge coil with an ohmeter. Proper readings and not shorted to ground. Would the flywheel rubbing the stator coil cause any problem? What do I need need next a High voltage meter to check outputs?
 
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