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1970 7.5 hp weird spark problem

M

Mercs

New member
SN- 2869197. Motor sat through heavy rainstorm and got water in the fuel system, it fired up like normal but then died. Got it home and drained the carb and put fresh gas in. Got it running again but it didn’t run good. Then randomly lost spark and now I am lost.
Wiring is brand new, new coils, new plugs, cleaned contact points and set gap.
If I have the wire from contact point for cyl 1 disconnected the other cylinder has spark and I can move it to both coils and they both spark but as soon as I connect contact point for cylinder 1 both cylinders lose spark.
I tried putting in new contact points for that side and soldered a new wire in, still no difference.
I don’t think it’s the stator as I have two (one the low speed doesn’t work but it still has spark) and that doesn’t make any difference.
Hopefully I explained this well and thanks in advance for any help!
 
2 sets of points to 2 individual coils. Each lead from coil (2 seperate colors) has a stud that passes thru the nylon insulator in the magnito housing to the point set.
Check these insulators for cracks. When the coil fires, spark will travel to ground thru the crack.
 
Droid said:
2 sets of points to 2 individual coils. Each lead from coil (2 seperate colors) has a stud that passes thru the nylon insulator in the magnito housing to the point set.
Check these insulators for cracks. When the coil fires, spark will travel to ground thru the crack.
Click to expand...
Would that cause both coils to lose spark? Because as soon as the brown wire is disconnected the white one has spark. Do the points work separately from each other?
 
I'm trying to remember the details. I have same motor, 1971 model. Uses same s/n range parts book. All I had to do was new points (both sets) & replaced 1 wire, brown I think because insulation was all deteriorated. That was 5 years ago.
I've encountered it on a similar vintage 20hp. New insulators fixed it.
 
Droid said:
I'm trying to remember the details. I have same motor, 1971 model. Uses same s/n range parts book. All I had to do was new points (both sets) & replaced 1 wire, brown I think because insulation was all deteriorated. That was 5 years ago.
I've encountered it on a similar vintage 20hp. New insulators fixed it.
Click to expand...
The more I read about these ignition systems the more regret buying it. I will closely inspect the plastic insulators and maybe try putting different ones in from my parts motor. I didn’t notice any damage to them when I put a new wire on the stud and I also lathered them up pretty good with liquid electrical tape.
 
Well I was very skeptical that that was the problem. Put in the best looking insulator from my parts motor now we have good healthy on both cylinders. Thanks a bunch for your help!!
 
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